The Literature.cafe server has a few different ones (like !fiction@literature.cafe, !nonfiction@literature.cafe, !classics@literature.cafe, !bannedbooks@literature.cafe, etc…), there are also places like !books@lemmy.world, !literature@beehaw.org, and !fantasy@lemmy.ml.

Books seems to be relatively active

It’s slightly off-topic, but there is a thing dedicated for that https://bookwyrm.social/