I think that veggies are such a healthy food group that any vegetable that my little dogs will eat; I am happy to feed it to them.
Now that I realize that they might actually like foods that I didn't think they would ( like the tomatoes), I am trying them on different foods.
I know they will pretty much eat anything that comes on a bite of pizza; but I have also been giving them some homemade soup with a lot of good veggies in the broth, and they really seem to gobble that down as well.
I am also giving them more raw veggies, which they do not seem to like nearly as well as they like the cooked ones; but they do chew on them for a while, and I always praise them when they make any effort at all to eat something new and different.