Boma at Animal Kingdom Lodge is a buffet experience.
Bier Garten at the Germany pavilion in EPCOT is without characters, but they do have a musical show and communal seating.
The Wave of American Flavors has a breakfast buffet.
Hoop de Doo - is all you can eat family style, so not really a buffet, it also has a show component.
I belive Spirit of Aloha is the same as hoop de doo.
O'hana dinner is also family style without characters, but there is a 'show' to get the kids involved.
Liberty Tree Tavern at Magic Kingdom is also without characters, but family style.
Apparently Centertown Buffet at Caribbean Beach resort is a thing too.
Swan and Dolphin have buffets as does the 4 seasons if I remember correctly.