Distinctive means instantly recognisable. "A sound like no other, is instantly recognisable and has an interesting and varied repertoire of sounds like no other?"
I challenge anyone to identify between a Merlin, a Griffon, a DB601 or Allison so I'd hardly call any of those instantly recognisable no matter how charismatic, and if you can identify between an Avon, Olympus, Conway, Sapphire, JT3 or Spey I reckon you're some kind of audio-signature computer! Ditto most turboprops.
None have a "varied repertoire of sounds" as far as I can tell.
Argus qualifies. motorbike to silence. Rather like my old BSA...
As might the Goblin, whine to howl to unique whistle.
Astazou is quite distinctive but hardly has a repertoire.
Dart too is distinctive-ish but some of the Soviet turboprops sounded just the same, and again has little in the way of repertoire.