Klarion was a good Kirby creation, and one of the few from Kirby's DC period that was later developed in an imaginative way by another writer - Grant Morrison in his Seven Soldiers project from a few years back.
Moondragon I really liked in the Englehart/Perez Avengers, but no one since has managed to do anything interesting with the character, as far as I'm aware.
The Human Target always sounded like a neat idea, but I haven't read any of the comics. I did try the pilot episode of the tv series, but wasn't tempted to carry on with it.
Destiny, was he strictly a framing character for introducing stories in the DC horror anthologies, or did he sometimes appear as an active agent in the main story? I like the visual in that panel, which I forgot to quote and reproduce here.