I mean there's Torbjorn and Reinhardt, but I definitely am missing the sagely old man archetype, and there definitely needs to be an old woman.
You can either go the badass route like Madame Webb from Spider-Man...
Obviously not spider-themed since that's Widowmaker's gimmick,
...or you could go full
Miss Marple/Super Gran style old granny-type lady, maybe even make her super tiny and ride a floating comfy chair or something. Make her come from one of those comfy countries - Ireland, Austria, Poland or something. Have her use an umbrella gun and throw exploding teapots or some shit. Have her go "Oh why hello deary." or "Would you like some jelly babies?", perhaps with a REALLY English accent. It'd be
amazing.