is there anything outside of uxie/spiritomb that can switch into medicham on balanced teams
Fat psychics and ghosts are the most effective way to check medicham in general. If it can take a high jump kick or make medicham not use high jump kick, you are fine against it.
So to summarize, adding what Kableye said, here is a list:
Psychic types like: Musharna, Hoopa, Slowking, Uxie, Sigilyph
Fairies like: Granbull, Aromatisse, (togetic manages to get 2hkod by zen headbutt after rocks)
Ghosts like: Cofagrigus, Spiritomb, Gourgeist, Jellicent
There is also fletchinder that fits really well on balance and can revenge kill medicham all the time but not a switch-in at all. Hoopa and sigilyph, even tho they arent fat, they can deal with cham thanks to their typing.
Good luck.