I have unironically been a bit obsessed with this interactive:

https://altcyoaisekaitheend.neocities.org/

(Warning, mildly lewd, extremely lewd if you go into the specific NSFW section).

The way it does it's powers as separate archetypes with capstones is pretty interesting and encourags build crafting, though there's some serious point scarcity and I think it could do with more general abilities to round out your build.
The two schools I like the most are Blue Magic and Puppet Magic, but shapeshifting and puppets are awkward to mesh together. I'm not really interested in the ability that turns you into a hivemind zombie plague either.