| Artist | Active | Genre & Styles |
|---|---|---|
| Plácido Domingo | 1950s - 2020s | Classical, Classical Crossover, Opera |
| Richie Havens | 1960s - 2010s | Folk, Pop/Rock, Folk-Rock, Singer/Songwriter, Early Pop/Rock, Protest Songs |
| Georgi Kostov | Classical | |
| Keith Barbour | 1960s | Pop/Rock |