2. Symmetra
Symmetra doesn’t have any healing capabilities. In fact, the closest thing she has to a healing technique is giving each of her allies a Photon Shield, which grants them an extra 25HP worth of armor, and it regenerates over time. However, this actually does give each and every of your allies some extra survivability. The Shields are particularly useful for low HP characters like Tracer or even Zenyatta. Even if Symmetra falls in battle, the Shields will stay active until the allies themselves die.
Symmetra is also fantastic for guarding control points. Her Sentry Turrets may only have 1HP each, but they will damage and slow down enemies, essentially making them sitting ducks for your allies to shoot at. As long as you place the Turrets in hidden locations where the enemy won’t think to look, the opposing team won’t stand a chance at taking over your control point. She also has a Photon Projector that can shoot beams to damage enemies, as well as orbs that pierce through shields. If you can slow down Reinhardt with a Turret, and then shoot him with orbs, he’ll go down pretty quickly.
Even though Symmetra can’t actually heal allies, she can bring them back into the fight very swiftly even if they fall. Her ultimate ability allows her to place a Teleporter in the field, and allies will be able to get there instantaneously from the spawn room. This essentially allows your team to keep the pressure on the enemy, and if used correctly, can even turn the tides of a losing battle.