It depends on how one-hit wonder is defined...in Joel Whitburn’s Top Pop Singles 1955-1993, he lists those artists who hit #1 while it was the only song of theirs that ever reached the Billboard Top 100.
A few are:
Laurie London-He’s Got The Whole World (In His Hands)
Silhouettes-Get A Job
Elegants-Little Star
Hollywood Argyles-Alley-Oop
The Singing Nun-Dominique
Zager & Evans-In The Year 2525