Via tor.com, I see that Marie Brennan (Tropic of Serpents) and Mary Robinette Kowel (Glamour in Glass) traded fanfic set in each other’s worlds. I think that’s charming.
Here is a link to Marie Brennan’s story: “A Classical Education.”
And here is a link to Mary Robinette Kowel’s story, “A Study in Serpents.”
I haven’t read either story yet, but I expect I will read at least the latter. I haven’t read any of Kowel’s Glamourist History books, so I doubt I’d appreciate fanfic set in that world.