Searching for folf should find basically the same results as searching for wolf fox hybrid, i.e. characters that are hybrids of wolves and foxes. (Ignoring cases like three characters in a post where one is a wolf, one is a fox and one is a completely different hybrid.)
Searching for folf currently finds **any** hybrid because it is aliased to hybrid. That seems unhelpful. wolfbird -> hybrid is another example.
It might be that you consider folf and wolfbird not to be distinct enough of a species to have it be a separate tag. But both of these do have wiki-pages (folf wolfbird) explaining them, so it seems like an oversight.