Dairy-based:
Whey - digested quickest (in isolation), best used as a drink
Casein - digested slower (than the above in isolation), typically used pre-bed, also works better for protein pudding/sludge/proats
Milk Protein - blend of both the above
Plant-based:
Soy - most common vegetarian protein source
Pea - found in things like Huel
Brown Rice - urgh, no
Hemp - urgh, no
I buy the milk protein in bulk because I liked to use it in proats, making protein deserts etc. It's cheap (per-kilo) and convenient/versatile, easy to take to work etc. If you aren't vegan I see little point in using the plant-based ones, since the bio-availability of the dairy-based ones is better and they're also complete in terms of amino acid profile and cheaper.