The Universe of Evil is an alternate universe in which the SuperFriends are actually evil. Here, they are referred to as the Super Enemies. What passes for law enforcement in this universe is aware of the Super Enemies, and has developed ways to combat them (for instance, police helicopters are equipped with Kryptonite lasers).
It is unknown if there are any heroic characters in this universe; however, given the existence of the Legion of Doom in the normal universe, it is possible that there is a "Legion of Good" in the evil universe.
Earth-Three was considered to be a partially "reverse" Earth and was populated by "opposites" to the primary Earths of the Multiverse. The majority of the Earth-Three's superpowered beings were criminals unlike the primary Earths whose main forces were heroic beings. The primary superbeings of Earth Three were five evil analogues of the Earth-One superheroes, called "The Crime Syndicate of America". The base populace of Earth-Three reflected a society based on laws and good values, despite the majority of their super powered beings having an evil nature.
Earth-148 was a parallel world, which contained elements from the Earth-One reality. However, in this reality, everybody's alignments were entirely different. Heroes from Earth-One are villains and viceversa, creating this sort of "evil twins" universe.
Season 4 (1979):