Fluke- who could forget Fluke, and the dog that helps him
Sparky- the little terrier on beethoven 1
Nepoleon- from the self titled movie
Greyfriar's Bobby
Bel Ria- the gypsy dog
Bruce- the seeing-eye dog on 3 lives of Thomasina
Gidget- the taco bell dog
Nipper- the RCA dog

I remember reading about Topper.