You will see the most and greatest variety of characters at Minnie's breakfast. Just walking by yesterday, I noticed Chip, Peter Pan, and the fairy godmother were visiting with guests in the outdoor seating area. The last time we actually went to Minnie's, I think we saw nine characters including Chip and Dale, Minnie, the fairy godmother, a mouse from Cinderella, Captain Hook, Max, and a couple of Winnie the Pooh characters. My brother was there a couple weeks ago and sent me pics of his kids with fairy godmother, Rafiki, Chip, and Eeyore.
Storyteller's has animal creatures from various movies. There are usually about 5 characters circulating. We have been there before and not managed to see both Chip and Dale, but they are supposed to be there. It's been a number of years since we have visited this one, so I don't really know who is there these days. In the past we have seen Brother Bear and Tarzan characters, Brer Bear, Baloo, Meeko, and a park ranger, not all during the same visit.
I hear Goofy's has changed to just having the same five characters at each meal and they are classic characters like Goofy, Minnie, and Pluto. I haven't been to Goofy's since the change so can't tell you more.