Here's a list of all Chaotic Evil Servants in this game:
https://gamepress.gg/grandorder/chaotic-evil
Some Servants pair well with Douman due to the massive buffs he grants and his debuffs, like Kama or Cu Alter IMO.
Tbh I really like in gameplay terms Servants like Van Gogh or Douman, that their buffs are also really good for their allies. It's a pity that I don't like the Servants themselves...