Kuwabara's voice
I'm actually watching through YYH for the first time (I only ever saw a couple episodes when I was younger) and Kuwabara's voice sounds incredibly familiar. There's another cartoon, anime, or video game or something that has a character with almost the same voice, but I just can't place it. I already looked through everything that the voice actor has done and couldn't find it, so it must be something else.
edit: Found it, Muscle Man from Regular Show