Um, I guess Ferdinand is a pretty sexy bull.

I'm the sexiest bull, obviously.

Hehehe, JK. I dunno about bulls in popular culture but I've always liked the boar guy in TMNT... although I can never remember if they're Rocksteady or Bebop. I'm always getting the two mixed up. XD

The boar from the movie The Boy and the Beast

uh bihorn from hunter x hunter is kind of a bull I guess?

Ganon

ganon, from hyrule warriors, and Taurus from gargoyles

Chester Hayes from Dynewulf's visual novel. Super adorable but handsome bull!

Emboar

Bull: Bogo from Zootopia
Boar: Iozen from the boy and the beast