Regarding Twitter's announcement, I can't think of a better reason to put your money to a more rewarding use than commissioning someone to make a custom avatar instead. It'll benefit an actual real person instead of a corporation, and you get something that's truly yours too!
Socel is a place for animation professionals, freelancers, independents, students, and fans to connect and grow together. Everyone in related fields such as comics, illustration, and video games is also very welcome. As an implementation of Mastodon, Socel connects you to almost two million users around the globe as part of the Federation; a network of independent social spaces communicating with each other.