After leaving Uriah Heep in 1976, David sang backing vocals on two tracks for the first solo album by Canadian artist Ian Lloyd.  This album also featured Mick Jones and Ian McDonald who later formed Foreigner in the same year.   Comments from Ian Lloyd himself is that he doesn't even remember David singing on the album.   This leads us to to believe that Byron just happened to be there at the time as a friend to someone else.

Tracks with Byron's backing vocals:

1. Brotherly Love
2. Ohh What I'd Do (For Your Love)

On a 1977 release by solo artist Peter Bliss, David sang background vocals along with Benny Mardonnes and Michael Sherman on the next to last track on side two.   The song "Waitin' For Love To Arrive" featured  the main artist on lead vocals so it's difficult to hear David's voice.

UK single release in 1979 by Denny Ball's band.  Produced by David Byron, speculation is he did sing backing vocals on it but that has never been confirmed.   Flip side of the single was "At A Distance".