I think just about every character in Bleach serves as comic relief one way or the other. XD

(Sorry! I only have the Kenpachi icons, by chomiji, and a Renji by kagome_taisho. But kagome_taisho made have made some, since she makes a lot. Her Bleach icon tag. (http://kagome-taisho.livejournal.com/tag/i-bleach))