While the two preeminent teams of super villains on Earth-S were the Sivana Family and the Monster Society of Evil, they were by far not the only ones in existence to bedevil that world's superheroes. For instance, there were the following felonious foils:
The Revenge Syndicate were a trio of tormentors for their mutual adversaries, Bulletman and Bulletgirl. They consisted of the Weeper, the Murder Prophet, and the Black Rat. Each of them has previously faced that gliding guardians in individual schemes, before realizing the benefits of joining forces. However, although each of its members attempted to lead this group on three separate capers, each time they met defeat.
Then there was six opponents of Mister Scarlet and Pinky, who joined forces under their former warden, who himself was secretly a Nazi fifth columnist seeking to use them against the country he now lived in. This man, the so-called Brain, picked Black Clown, Horned Hood, Black Thorn, Laughing Skull, the Ghost and Doctor Death. Although none of them has special powers, relying on gimmicks and duplicity, they learned that together they still were no match to the Dynamic Duo.
Similar to Flash's Rogues Gallery and the Fearsome Five/Five Fingers of Earths One and Two that faced the Fastest Men Alive and the Teen Titans/Law's Legionnaires respectively, their notoriety was less known than their contemporaries given the brief one-and-done nature of their amoral alliance.