I love this question because I think you'd be surprised by the exhaustive list of extra-U2 musical collaborations and projects that Bono has been involved in. I'm going to do my best to provide just such a list now... read more
Sinead O'Connor: In addition to the collaboration with Gavin Friday, Bono also collaborated with Sinead on the song "I'm Not Your Baby" for the Wim Wenders movie, The End Of Violence. Leonard Cohen: OK, this is a stretch, but Bono recorded a cover of Cohen's famous song "Hallelujah" for the tribute album, Tower Of Song. read more
Outside the band, he has recorded with numerous artists. He has collaborated with U2 bandmate the Edge on several projects, including: songs for Roy Orbison and Tina Turner; the soundtracks to the musical Spider-Man: Turn Off the Dark and a London stage adaptation of A Clockwork Orange; and the refurbishment of the Clarence Hotel in Dublin. read more