The Vocaloid Database (VocaDB) and it' sibling site Utaite Database (UtaiteDB) seem to be a pretty extensive sites for Vocaloid/Utau songs, albums, artists and events. I would like to recommend they be added to the other database whitelist.

URL examples:

• Artists / Groups / Labels:
  • http://vocadb.net/Ar/1
  • http://utaitedb.net/Ar/1

• Album:
  • http://vocadb.net/Al/2263
  • http://utaitedb.net/Al/4644

• Song (work & recording):
  • http://vocadb.net/S/23552
  • http://utaitedb.net/S/12051

• Event series:
  • http://vocadb.net/Event/SeriesDetails/1
  • http://utaitedb.net/Event/SeriesDetails/5

• Event:
  • http://vocadb.net/Event/Details/23
  • http://utaitedb.net/Event/Details/1046

Patterns:

http://(?:uatu|voca)db\.net/Ar/\d+
http://(?:uatu|voca)db\.net/Al/\d+
http://(?:uatu|voca)db\.net/S/\d+
http://(?:uatu|voca)db\.net/Event/SeriesDetails/\d+
http://(?:uatu|voca)db\.net/Event/Details/\d+