Lots to choose from...
Sunshine Seasons had the biggest selection of desserts of the places we went to. They are located in The Land pavillion at Epcot... I don't even remember all of the selections, but it is a whole bakery case with cakes, pastries, pies..all fresh and delish...
I also enjoyed Wolfgang Puck Express at DTD. HUGE cookies, brownies and the best Key Lime Tart I've ever had... definitally worth the trip...
Most other CS have the usual, chocolate cake, carrot cake, cheesecake all in single serving containers...
I found that a lot of times we were so full from our entrees that we took the desserts with us... made good snacks back in the hotel room..