Okay, I've had it at countless weddings, and I just don't know what cake it is. It has crushed pineapple bits, pecans, and like a yellow mix...is it italian creme cake or some other type?

Italian creme has coconut and pecans, certainly no pineapple.
Hummingbird has coconut, pineapple, banana and may have pecans.

Sounds like hummingbird.

Sounds like Pappadakis Carrot cake or Hummingbird cake.