The Masters of Evil were a team of supervillains. There have been eight incarnations of the Masters of Evil, accumulating dozens of members in total. The Masters of Evil were primarily opposed to the Avengers, although they also battled the Thunderbolts (ironically consisting of former Masters of Evil) and the Guardians of the Galaxy.
Current Version:
The Masters of Evil (Baron Zemo's Second Team)
Versions:
The Masters of Evil (Original)
The Masters of Evil (Ultron's Team)
The Masters of Evil (Egghead's Team)
The Masters of Evil (Baron Helmut Zemo's Team)
The Masters of Evil (Dr. Octopus' Team)
The Masters of Evil (The Original Thunderbolts)
The Masters of Evil (Crimson Cowl's First Team)
The Masters of Evil (Crimson Cowl's Second Team)
The Masters of Evil (Shadow Council)