Counterspells, protection spells, metamagic.
Creating items and creatures, and summoning creatures.
Seeing and learning, including predicting the future.
Enchanting, bewitching, bethralling and charming other people.
(Traditionally, evocation, invocation and conjuration and summoning are four words for the same thing. Calling forth the entity… But in D&D…) evocation means creating powerful elemental effects. Such as fireball.
Creating images and sounds and smells that aren’t really there. Seems weak compared to conjuration where the things are there for real, but… you can do bigger stuff easier & cheaper.
Necromancer raise the dead and let me see them fight
Changing things from one to another. Prestidigitation, shillelagh, and mending are all transmutation spells, as is barkskin.