ooh is there a list of piefed instances from most popular to most endorsements?

There’s a built-in instance list on piefed when you click on “register”. It’s sorted by server speed. The most popular must be piefed.social.

And specifically ones that tailor to solarpunk/anarchism/lgbtq+?

In reverse order, piefed.blahaj.zone for a lgbtq+ instance, and anarchist.nexus as well as quokk.au for anarchist ones. @povoq@slrpnk.net mentioned the possibility of a solarpunk piefed instance in the past, but it’s yet to become something concrete.

i wonder why everyone shifted to piefed? is it because one of the lemmy devs had a controversial past?

I think it’s half because piefed has more feature, develops faster than lemmy, and half because the lemmy devs are pricks (one being a transphobe, and the other not being all that bothered by it).