The Alternate Universe worlds in which Harry Potter is raised by Remus Lupin, Danger Granger Lupin, Aletha Freeman Black, and Sirius. His siblings and pack-mates are as follows: Draco Reggie Black, Hermione 'Neenie' Granger Lupin, Meghan Lily Black, Luna Lovegood, Ron and Ginny Weasley, and Neville Longbottom. It is characterized by a mostly wonderful, occasionally evil style in which there are happy endings, cute songfics, intellectual intrigue, and epic battles. Oh, and DB/LL as well as MB/NL.
The Dangerverse has a story where one version of Harry Potter sings Christmas songs while another fights Voldemort. Don't you just love crossover fics?