So to my immense joy, Hexbear has started appearing on the front page again. Instance blocking is not available, and even the regular block feature sometimes fails (on certain communities?) for no clear reason. I've already tried blocking their "DuNk tAnK" and politics sub, it errors in a way that doesn't seem to happen otherwise. No idea why - more info on error pages would be nice - and I'm curious if that's reproducible for anyone else. (I'll hold off on being overly conspiracy-minded, but isn't it quite interesting that it doesn't seem to happen to other instances...)
As a stopgap measure I've hacked together these uBlock Origin compatible filters. Fairly easy to change if you want to block other/additional instances - or narrow it to specific Hexbear communities, though I can't imagine why you'd want to.
! https://kbin.social block any post to hexbear communities kbin.social##article.entry:has(aside.meta > a.magazine-inline[href$="@hexbear.net"]) ! https://kbin.social block any post from hexbear users kbin.social##article.entry:has(aside.meta a.user-inline[href$="@hexbear.net"])