If there's one member of the huge Legion of Super-Heroes roster that I think is suited for their own solo series, it has to be Ultra Boy. I have just always loved the fact that he has a large and varied power set, but can only use one super ability at a time. His Legion Flight ring allows him to cheat a bit and use two powers at once, technically. Still, it's a unique set up that no other hero has and I'd love to see it explored further.
Galactus Previously faced off against the entire Legion of Super-Heroes in STF #1487 and then again in STF #1985...
