So, I know I can block communities, but is there a way for me to block instances? It looks like some instances are becoming specialized in their content, which is great, and I think a way for the Fediverse to grow sustainably and healthy, but there’s going to be instances centered around things I’m just not interested in. Is there any way for me to block them from my “all” feed?
Not yet. Eventually it’ll be a thing. That said, expect the ALL feed to be very messy. It’s better for now to curate feeds via Subscribed timeline until that feature is implemented.
That said it should be trivial to create a userscript that filters out posts from certain remote communities.