Hmm…I guess Robert Hunter would fit in here.
He wrote the lyrics to many of the Grateful Dead’s songs, but was never actually a performing member of the Dead. Kind of like Brian Wilson and the Beach Boys. He does play live solo concerts where he does solo acoustic takes on many of the Dead songs that he wrote the words to. He also plays many of his own songs that the Dead never played, as well as some covers of other people’s songs.