Been thinking about this since dear Dolly and the fact that 9 to 5 is finally a proper hit in chart terms.
So far I've got Glitter and Morrissey.

Who haven't been discovered to be criminals*Thinking about the oldest pop stars still living who aren’t criminals. Maybe Petula Clark? Although I do love her so.
I also imagine non singing members of famous bands wouldn’t have all that much impact. When Charlie Watts died, it didn’t significantly bump numbers for The Rolling Stones. I don’t even think Jackson 5 numbers went up by much when Tito died.
Otis Williams is also the last surviving Temptation. Since the rest of them popped off decades ago, I can’t imagine it’ll give the catalogue a boost.