Is George Orwell's Animal Farm on topic here? It is clearly not Sci-Fi but could we consider it Fantasy?
I'm going to add my own for and against answers for voting, but of course that doesn't preclude any other answers!
The discussion of anthropomorphised animals has come up before. Quoting from the most upvoted answer on that thread:
Anthropomorphic/Sentient/Talking animals don't, in and of themselves, make a film/book/TV programme/comic into a fantasy if the central conceit is that talking animals do already exist within that fictional universe.
Animal Farm falls squarely into this category, and thus is off-topic. (At least, I think so. I don't recall the talking animals being depicted as unusual in-universe, although it's been years since I read it.)
Aside from the talking animals, the rest of the book is a political allegory which has nothing to do with sci-fi or fantasy.
Leaving out any consideration of talking animals, the plot of Animal Farm involves a group of farm animals driving out the human owners of their farm and then continuing to run it. Unless you consider this to be something that could happen in the real world, then surely it must be fantasy.
The fact that it is also political satire doesn't prevent it from being fantasy any more than the fact that The Hitchhitchhiker's Guide to the Galaxy is also comedy prevents it from being Sci Fi.