EXCELLENT Sherlock AU that is set in the Bronte juvenilia universe of Gondal
I tried, I really tried to read this series, because I am a huge Sherlock fan, but I just couldn't. I don't know if it was the thought of wading through all those fics (bit of a hypocrite if you read my next paragraph) or if it was that they paired Sherlock off with an OFC, but I just revolt at that, I'm too much a Johnlock shipper.
If you like fics that are set in real historical times, I can recommend a couple of series. One is very long, twenty some odd parts, but I don't think any of them are more than about 5k words, so they're relatively easy reads, and takes place during WWII. Sherlock works at Bletchly Park and John gets invalided back from Africa. Lots of period typical hiding their sexuality and all. Long Ago and Far Away by lotherington. I haven't finished the series yet because it's so easy to stop and then pick it right back up again.
I love historical stories even if they aren't a completely AU setting of the original. I found a War Horse fic where Jim Nicholls didn't die on the field and he rescues Jamie from a prison camp. Very angst-worthy and lots of h/c. Roses of Picardy by splix. I actually found it because she writes Sherlock fic, but this piqued my interest. It's probably the only War Horse fic I will ever read, because it's become seminal for me. Again, lots of period typical homophobia, plus class barriers.