We saw Jasmine by Aladdin's Oasis. We also saw a bunch of characters around Town Square at different times...Mickey, Minnie, Cruella de Ville, Alice and the Mad Hatter, Goofy..
Mickey we also found at his house in ToonTown. I know Minnie sometimes appears at her house back there as well.
At DCA we took pictures with Mater and Lightning McQueen across from Soarin. We also ran into Mr. Incredible and Sully on the corner across from the Hyperion Theatre in the Hollywood Backlot. Woody, Princess Aurora, and Sorcerer Mickey were available for pictures after the Drawn to the Magic show that happens (sometimes in front of the Animation Academy, sometimes on the stage across from Monster's Inc.)
We also ran into Jessie at the Carnival games near Toy Story Mania.
The Little Green Army Men from Toy Story also do a fabulous performance that should be on the times guide. Highly recommended!
Oh, and there's always Pixie Hollow and Princess Fantasy Faire for structured meet and greets.
ETA: On a separate occasion we also saw Aladdin and Jasmine together inside the Aladdin's Oasis area for pictures. When Jasmine was by herself, she was in the little courtyard area off to the right of the Oasis.