Simba has waaaaaaaaay too many to list but here are a few:
Sim, Simmerz, Simbalou, SimButt2, Stinkz, Stinkums, Tinky boy, Tink tink, Tim Tim [ originated as "sim Sim"] Fartzie Boy, Sweetie [this is used when hes been alone all day and i missed him or if i accidently step on his paw or hurt him in some way] Buttsy boy, Gay Boy.... and there's plenty more.