I used to maintain a recs site (I haven't touched it in about six years), and I had a crossovers section. I don't guarantee all or even most of these stories are still there. I haven't checked in years. They are all things I liked a lot, though.

I've written a few crossovers. If you're interested in self-recs, I can dig up the urls for those on either my personal site or AO3. I'm not sure you'll know any of the fandoms, however.