1)  Symmetra:  Torbjorn benefits from Symmetra's Photon Shields due to his poor mobility to reach health packs and it can keep Torbjorn alive a bit longer.  Photon Shields compliment Torbjorn's armor pack allowing him to have an overall larger hitpoint pool.

Symmetra also benefits from Torbjorn's Armor Pack, as it can allow her to withstand more damage especially while attacking enemies up close with her Projector Beam.

NOTE:  I'll mention this once here.. Armor obtained from armor packs cannot be healed and allies will have to pick up a new armor pack to obtain more armor.

Torbjorn can place his Turret in a position where it can guard Symmetra's Teleporter or Sentry Turrets.  Enemies attacked by Sentry Turrets will be slowed which can give more time for Torbjorn's Turret to output more damage.  This can be a very powerful defense together.

Symmetra's Sentry Turrets can also be placed in rooms/hallways to guard choke points leading up to Torbjorn's Turret to protect it from offensive flankers.

Due to Torbjorn slow mobility he greatly benefits from using Symmetra's Teleporter to get back to the fight faster after dying, especially if he doesn't have his turret out at the time of his death.

If Symmetra is getting flanked, she can go towards Torbjorn's turret for cover.  Torbjorn can further protect Symmetra with Molten Core to really scare enemies away from her.

2)  Ana:  Torbjorn usually stays in the backlines while maintaining his turret.  Even though he can provide himself with armor packs, his poor mobility makes it hard for him to reach for health packs quickly so he benefits from the occasional heal from allies.  Ana's Biotic Rifle heals are an easy way to keep Torbjorn healed up, allowing him to stay near his turret to guard it.

When picking up Scrap in the front lines, Ana should pay special attention to Torbjorn and she should give him Biotic Rifle heals as he needs it.  Ana's Biotic Grenades can also help increase your survival, especially if there is another healer on the team.

Ana can receive an armor pack from Torbjorn, this can allow Ana to survive flanks more effectively.  Luckily, Ana is usually not to far from Torbjorn and can get new armor packs easier than offensive heroes can.

Torbjorn is a decent candidate for Nano Boost.  Nano Boosting Torbjorn allows him to safely move into the front lines to pick up Scrap while also dishing out more damage as well.  If you decide to use Molten Core with it you will get a lot more use out of it.  Even though your turret will be unaffected by the Nano Boost, Torbjorn himself will be able to do a lot of DPS while being practically invulnerable for Nano Boost's duration.

3)  Mercy:  Since Torbjorn spends a lot of time staying in one area building/repairing his turret, he is very vulnerable to damage.  His low mobility makes it hard for him to dodge enemy fire and to seek health packs.  Torbjorn can give himself (and allies) Armor Packs which gives him +75 armor (that cannot be healed), which does provide a little extra protection until damage eats away at his native HP pool.  Torbjorn's ultimate Molten Core does NOT heal up his health pool, but it does increase his armor temporarily.  Because of his lack of means to gain health, he benefits from Mercy's (and other allies) healing capabilities.

Torbjorn is usually a safe hero for Mercy to support because Torbjorn generally stays in the backlines keeping a watch over his turret and doesn't wonder to far from his team.

Mercy greatly benefits from Torbjorn's Armor Packs and she is a prime candidate for it as well.  Most enemies try to go after Mercy first, so she tends to take a lot of damage.  Keeping Mercy alive with a constant flow of Armor Packs will help keep your whole team alive.

Mercy's damage boosting beam can be effective with Torbjorn, but only when he is attacking something and not repairing his turret.  Damage boosting Torbjorn's Molten Core tends to be very effective.

Torbjorn's slow mobility makes it longer for him to run back to the fight after dying, so he does benefit a lot from Mercy's Resurrect, especially if he doesn't have his turret out at the time.

4)  Lucio:  Torbjorn greatly benefits from Lucio's auras due to his slow mobility.  Heal aura can keep Torbjorn going strong without worrying about reaching for health packs as much, allowing him to spend more time with his turret to keep it repaired.  Speed aura helps Torbjorn maneuver around quickly to repair his turret, pickup scrap, fire shots at his enemies, quickly throw down Armor Packs for allies to get, and to dodge enemy ultimates.  Keep in mind that Lucio's auras only work when you stay within 30 meters of each other and keep line of sight with him as well, which both Lucio and Torbjorn generally do together most of the time anyways.

Lucio's Soundwave (knock back ability) can keep dangerous close up enemies away from Torbjorn, including:  Mei's freeze gun, Reaper's shotguns, Reinhardt's rocket hammer, and McCree's fan fire.  Lucio can also use a Soundwave to knock enemies into Torbjorn's turret's line of sight.

An Armor Pack for Lucio can help him survive a bit longer, which can keep his auras on the rest of your team more consistently.

It's generally better to wait and use Molten Core at a different time that Lucio uses his ultimate Sound Barrier.  Sound Barrier provides temporary shields, but Molten Core works similar for Torbjorn by providing +300 extra armor for a short time.  By spacing them apart you will effectively stay alive longer and be able to stay more aggressive.

Lucio's Sound Barrier can make it easier to go in the front lines to pick up Scrap, which in turn can supply more Armor Packs for your team.

5)  Zenyatta:  Zenyatta's Harmony Orb can be thrown on Torbjorn if he needs healed up, which is more efficient than running to a health pack due to his slow movement.  But keeping the Harmony Orb on Torbjorn after fully healed is not as efficient as it being kept on other offensive flankers.  Also, having the Harmony Orb on you can make it safer to go in the front lines to pick up Scrap.

Torbjorn's Armor Pack is extremely useful for Zenyatta because has native HP pool is only 200, having a +75 Armor Pack on gives him 275 HP, which is substantially more and can allow Zenyatta to take headshots and live from many weapons in the game.  Keeping Zenyatta alive maintains his Orbs on his selected targets.

Be mindful of which enemy that Zenyatta puts his Discord Orb on, as that will be a prime target for you to attack with Torbjorn's Rivet Gun, as it will do 50% more damage to the target.

Just like with Lucio's Sound Barrier, it's generally better to use Molten Core at a different time than when Zenyatta uses his ultimate Transcendence.  Transcendence will rapidly heal you, but so does Molten Core slightly (+300 armor), so it's generally better to space the two part so you can be more aggressive and have survivability longer.

Zenyatta can use his Transcendence to protect Torbjorn's turret by blocking shots with the large hitbox of Transcendence.  Transcendence can also make it safer to run around and pick up Scrap.

1)  Reinhardt:  Reinhardt's shield pairs very well with Torbjorn.  Torbjorn and his turret can safely attack enemies from behind Reinhardt's shield.  Shielding a turret will enable Torbjorn to focus on using his Rivet Gun more instead of constantly repairing his turret.  Reinhardt's shield can also enable you to run around safely to pickup Scrap.

Out of all the tanks, I believe that Reinhardt benefits the most from Torbjorn's Armor Packs.  Reinhardt is overall a very vulnerable hero without the help from his allies to provide healing or protection in some way.  Armor Packs increases his survivability, especially when charging around at enemies, exposing himself to more danger.

Reinhardt's ultimate Earthshatter will drop/stun enemies to the ground for a short time giving Torbjorn an easy opportunity to dish out Rivet Gun damage and further protecting your turret from taking damage as well.  If there was a lot of enemies dropped from the Earthshatter and your turret is able to fire at them, consider using Molten Core at this time to take out the rest of the enemies.

2)  Winston:  Winston's Barrier Projector can allow Torbjorn to safely repair his turret or dish out Rivet Gun damage from inside the barrier, which can further take the need away from reaching health packs as much.  Barrier Projectors can allow Torbjorn to safely go up in the front lines to pick up Scrap.  Winston's barrier can also pair well with Molten Core, as Torbjorn is still slightly vulnerable while using it.

Out of all the tanks, I think Winston benefits from Torbjorn's Armor Packs the 2nd most (after Reinhardt).  Winston often Leaps up close to his enemies which can be punishing to his hitpoints by taking a lot of damage up close.  Armor Packs increases his survivability and reduces his need for healing as much.

Winston's ultimate Primal Rage can be beneficial for Torbjorn by batting enemies away from him, or knocking enemies into a turret's line of sight.

3)  D.va:  D.va's Boosters can knock down enemies which can make it difficult for enemies to take out turrets fast enough.  D.va can protect Torbjorn and his turret with Defense Matrix, which will also increase Torbjorn's survivability while repairing his turret.

Armor Packs have mediocre use with D.va.  Increased armor will simply increase the survivability of D.va's mech a bit longer, allowing her to stay close to her enemies and dish out Fusion Cannon damage for a longer duration before needing to boost to health packs.  If D.va's mech gets destroyed, she pops out of it and only has 150 HP, giving the little D.va an Armor Pack will greatly increase her survivability to dish out blaster damage with her Light Gun until she can call down a new mech.

D.va's ultimate Self-Destruct can pair well with Molten Core combined with your turret, but only if the Self-Destruct is done in such a way that forces enemies to run into Torbjorn's turret, which is usually not the case.  But depending on the map, you can build your turret in a spot where enemies could run into if struck by a Self-Destruct.  However, this might take some planning.

4)  Zarya:  Zarya's Projected Barriers can be effective on Torbjorn, especially when he is trying to repair/upgrade his turret or run in the front lines to pick up Scrap.  Other than that, Projected Barriers get less use from Torbjorn than other heroes would.  Zarya's personal Particle Barrier can provide a shield for Torbjorn and his turret from taking extra damage.

Even though 50% of Zarya's health consists of regenerating shield, she can still benefit from having an Armor Pack on, but not nearly as much as other heroes would.  This means, it's generally better to give more "squishy" allies an Armor Pack before Zarya.

When Zarya uses her ultimate Graviton Surge there really isn't anything special Torbjorn can do to kill all the clumped up enemies in the surge besides doing Rivet Gun shots and possibly using Molten Core so you can fire more rapidly at all the bunched up enemies.

5)  Roadhog:  Roadhog is an independent tank that doesn't have many synergies with Torbjorn.  When Roadhog Chain Hooks an enemy into him it can expose the victim to Torbjorn turret, this can ensure the death of the chained in victim.  Every time Roadhog Chain Hooks an enemy into him there is going to be a good chance that an easy to collect Scrap piece for Torbjorn can be collected from the death of the chained in victim.

Out of all the tanks I believe that Roadhog benefits the least from Armor Packs due to his already large hitpoints of 600 and his self-heal of 300.  Even then, Armor Packs can still help him a little to soak up even more damage in the front lines and to delay the use of his self-heal for a later time.  Armor Packs are most useful on Roadhog while he is using his ultimate Whole Hog as he is generally vulnerable while using it and he cannot use any other abilities (including his self-heal) until the ultimate is over.

1)  Widowmaker:  Widowmaker's ultimate Infra-Sight doesn't help Torbjorn as much as other heroes, since turrets cannot take any advantage of it but Torbjorn's Rivet Gun can be aimed slightly ahead of time to shoot at enemies coming around corners.  Infra-Sight can also make it safer to run around and pick up Scrap, as you will be able to see any threats approaching your way.

Widowmaker's Venom Mines can be placed in a position to protect Torbjorn and his turret from offensive flankers.

Widowmaker can always grapple towards Torbjorn's turret if she needs a place to provide protection from flankers.  Widowmaker can also attempt to lure enemies into the turret and Molten Core can be used if she brings a lot of enemies with her.

Widowmaker greatly benefits from Armor Packs since she is a relatively squishy hero and can normally be headshotted to death from full health with one hit from some weapons in the game.  Armor increases her survivability against offensive flankers, allowing her to grapple away from them in time safely.

2)  Soldier 76:  Armor Packs for Soldier 76 are not as useful compared to other allies because he can just use his Biotic Fields to heal up damage.  However, he does greatly benefit from picking up an armor pack right before using Tactical Visor, which will help his survivability while using it as normally he is a bit vulnerable while using his ultimate.

Soldier 76's Biotic Fields can be very beneficial to Torbjorn, as he is usually around in the same area as Soldier 76.  Torbjorn's poor mobility makes it hard for him to reach health packs, so Biotic Fields are very useful to him.

And of course Torbjorn's turret provides a nice DPS support for all his allies and can allow a nice defense for Soldier 76 to safely retreat to.

3)  Mei:  Armor Packs will provide some extra protection for Mei, and luckily Torbjorn is usually not to far from Mei and can get new armor packs easier than offensive heroes can.  Armor Packs can enable Mei to be more aggressive with freezing enemies up close and delaying her Cryo-Freeze a bit later.

Mei can prevent enemies from running away from Torbjorn's turret by walling them in with Ice Walls, or freezing them with either the freeze gun or Blizzard.  Ice Walls can be positioned so it can make it safe to run in the front lines to pick up Scrap.

Molten Core can pair well with Mei's Blizzard, as the extra DPS from Molten Core can make easy work of the frozen victims.

4)  Pharah:  Armor Packs will increase Pharah's survivability.  When landing on the ground from a Jet Pack, she can grab an Armor Pack before jet packing again so she can survive more shots while hovering around in the air.  The little extra armor could also help her survive while using her ultimate Barrage.

Torbjorn's turret can provide Pharah with a safe area to fly around for extra protection.  Pharah should always be mindful where Torbjorn places his turret at, and she should try to keep line of sight with it for better protection.  If Pharah uses Barrage, Torbjorn can activate Molten Core to further protect her while Barraging, it's not the best protection, but it can provide some support.

Torbjorn is strong against many of Pharah's counters, including:  McCree, Roadhog, Zenyatta, and Genji.

5)  Junkrat:  Armor Packs will provide some extra protection for Junkrat.  Luckily, Junkrat is usually not to far from Torbjorn and he can get new Armor Packs easier than offensive heroes can.

Junkrat can place his traps and mines to protect Torbjorn's turret from getting ambushed by offensive attackers.  Trapped enemies are very easy for Torbjorn to shoot with his Rivet Gun.  Junkrat can also place his Concussive Mine in a spot that will propel enemies into a turret's line of sight, so the turret can deal a good amount of damage to the victim.

If Junkrat is in any kind of trouble he can do a mine jump towards Torbjorn's turrets to take cover and potentially lure enemies into the turret's line of sight.

Unfortunately, Torbjorn's Molten Core doesn't really synergize with Junkrat's ultimate Rip-Tire much, except it can be a powerful force when dealing with an enemy push.

6)  Hanzo:  Hanzo's slow mobility to reach health packs makes Armor Packs very beneficial to him and Hanzo is usually not to far from Torbjorn and can get new armor packs easier than offensive heroes can.

Hanzo's Sonic Arrow can allow Torbjorn to fire his Rivet Gun before enemies come around corners, and it can allow him to take cover in time if he needs to.  Sonic Arrows can also allow Torbjorn to safely run around and pick up Scrap, as the Sonic Arrow can reveal incoming threats in the area.

Hanzo can potentially launch a Dragonstrike to make enemies flee into Torbjorn's turret to take them out.  Torbjorn can also combine this strategy with Molten Core to make it even more powerful.

7)  McCree:  McCree's slow mobility to reach health packs makes Armor Packs very beneficial to him.  Luckily, McCree is usually not to far from Torbjorn and can get new armor packs easier than offensive heroes can.

McCree can lure enemies into Torbjorn's turrets and then Flashbang them so the turrets can have some easy hits on them, McCree can then finish them off with a Fan Fire attack.

8)  Bastion:  A Bastion Sentry's stationary nature makes him very vulnerable to damage.  With Armor Packs he can survive a bit longer before needing to use his Self-Heal.  Since both Bastion and Torbjorn are defensive heroes, they typically stick close together, so Bastion is usually around to obtain new armor packs from Torbjorn.  Torbjorn can also easily throw an Armor Pack right on top of a Bastion Sentry, which can make getting more armor for a Bastion very easy.

Torbjorn's turret can provide some decent DPS to supplement a Bastion Sentry's DPS, the two combined provide a great defense against attackers trying to push forward.  Torbjorn's ultimate Molten Core can make the defense even stronger by turning the turret to level 3, which can make it incredibly difficult for attackers to break through it.  Bastion can take this strong defense up another notch by using his ultimate Tank Form at the same time Torbjorn uses Molten Core.  This strategy is especially useful when being overwhelmed with a lot of enemies close up.

9)  Genji:  Torbjorn's Armor Packs are very useful to Genji as it can allow him to absorb more damage before needing healed, this keeps Genji in a flanking position more often.  However, Armor Packs are not as useful as Symmetra's Photon Shield for Genji, since it does not replenish itself, as he will have to pick up a new Armor Pack to gain more armor again, which can be a nuisance for Genji to constantly backtrack to Torbjorn for new Armor Packs.

Torbjorn's turrets can allow Genji to retreat from a losing battle quicker by getting in the line of a turret's sight, thus keeping enemies away from him while he seeks healing.  Genji can also possibly lure enemies into Torbjorn's turrets as well.

10)  Reaper:  Armor Packs are useful to Reaper as it can allow him to absorb more damage before needing to use a Shadow Wraith to escape out of combat to get healed.  However, Armor Packs are not as useful as Symmetra's Photon Shield for Reaper, since it does not replenish itself, as he will have to pick up a new Armor Pack to gain more armor again, which can be a nuisance for Reaper to constantly backtrack to Torbjorn for new Armor Packs.

Torbjorn's turret provides a nice steady DPS from a distance, giving Reaper an easier time harassing and flanking.

11)  Tracer:  Armor Packs are very useful to Tracer as it can allow her to absorb more damage before needing healed.  However, Armor Packs are not as useful as Symmetra's Photon Shield, since it does not replenish itself, as she will have to pick up a new Armor Pack to gain more armor again, which can be a nuisance for Tracer to constantly backtrack to Torbjorn for Armor Packs.  Also, normally Tracer's Recall will put her in the exact state she was in a few seconds ago, the only exception to this is that it will not replenish damaged armor obtained from Torbjorn's Armor Packs.

Torbjorn's turret can allow Tracer to retreat from a losing battle quicker by getting in the line of a turret's sight, thus keeping enemies away from her while she seeks healing.  Tracer can also possibly lure enemies into Torbjorn's turrets as well.

12)  Torbjorn:  One of the main benefits of having multiple Torbjorns on a team enables each one to have a wider spread of picking up scrap, since each Torbjorn will be able to pick up their own separate Scrap piece from each dead enemy or ally.  This allows them to produce more armor packs for everyone on the team.  Remember that Armor Packs do not stack from multiple Torbjorns.

Setting up multiple turrets to guard a specific area can be a very powerful strategy, especially if you can protect them with a shield from either Reinhardt or Winston.  Unfortunately, you will be unable to repair another Torbjorn's turret though.