The last one I had
...was Rafiki from Lion King, seated in the lotus position. I still have him, but this flat-screen monitor doesn't have enough width for mascots to sit upon.
At work, on my old-fashioned CRT, is a fox (natch). Not a pop culture tie-in character, but from a child's animal play set. I have a tiny collection of foxes (i.e., 5 or 6), all gifts from friends. Come to think of it, Rafiki may be the only character I've managed to collect.
Not that I haven't wanted to... but, without children as an excuse, I haven't been able to convince myself to buy a meal of questionable nutrition for the toy.