Not everywhere is open for lunch, but on the monorail for 1 TS credit are:
Contemporary:
Chef Mickey (open for lunch seasonally)
The Wave (open for lunch)
Polynesian:
Ohana (breakfast and dinner)
Kona Cafe (breakfast, lunch and dinner)
Grand Floridian:
Grand Floridian Cafe (breakfast, lunch and dinner)
1900 Park Fare (breakfast and dinner)
Over at the Wilderness Lodge (boat ride from MK) for 1 credit, you've got the Whispering Canyon Cafe.