I loved Gash Bell. Did you read the manga as well, there is an arc after Zeno with a villain who makes Zofis look like a nice person. It's a long series though so it's not what Jessweeee♪ is looking for.

Full Metal Panic. So you can watch Fumoffu without wondering who everybody is.

I've been thinking of watching Psychic Detective Yakumo myself. It has some good reviews and the premise looks promising. It's a shorter series (13 episodes) too, which looks to be your style.