On Lemmy? No, though that is in the pipeline.
Kbin allows you to block entire instances though, if you're not averse to making a new account on a different instance.
Wait how do I do this
Go to kbin.social/d/\ ("d" for Domain), e.g. https://kbin.social/d/hexbear.net. In there on the sidebar you'll see the Follow button; next to it will be the block button. Hit the block button and that's that.
Works on any instance running kbin, though there's only 4 right now IIRC.
Kbin.social is a big one that is run by the developer if I recall correctly.
If you're using the connect app (if not, you should try it!), just tap the three dots any post you see by them, and click "block instance." Easy peasy.
Home of the sh.itjust.works instance.
