Fantastic recs, as always. I second 'as i let you rewrite gravity' - the absolute best Harry Potter crossover I've come across.

If you liked Rhyme, I also strongly recommend Parallel (http://archiveofourown.org/works/205389/chapters/305209) by brbsoulnomming (Sherlock/John and OC/OC F/F, rated M), which was written in response to the same prompt. The OCs are really engaging, and the developing relationship between Sherlock and John (complete with some agonising sexual tension) is very nicely done.