The World's Greatest SuperFriends (1979)

This iteration of the Superfriends program contained full half-hour episodes which were among the darkest of the superheroes' careers. It featured only Superman, Wonder Woman, Batman, Robin, Aquaman, and the Wonder Twins. Their adventures took them into underground kingdoms of dwarves, mushroom worlds populated by tar creatures, transformed them into vampire bats, pitted them against the Super enemies of an alternate dimension's Hall of Evil, and even a planet Mr. Myxyzptlk has based on L. Frank Baum's land of Oz.