There's this github repo which is full of websites that also offer onions, maybe that doesn't count. Some I know are

Dread

http://dreadytofatroptsdj6io7l3xptbet6onoyno2yv7jicoxknyazubrad.onion/

GitHide: Git, but hidden

http://githidep2hynhdmutuv7n2tei4iie2c7lyqz5fes3r5zzoxe5dshtxyd.onion/