The church we left last May would have a church-wide Thanksgiving potluck the Sunday prior to Thanksgiving. The church bought the turkeys and a ham. The church is about 75 people and most would come for that potluck, and bring guests. It would take some creative thinking and dedicated staff to do that with a larger church, I think.
The church we have been attending since May has a special service of praise the Sunday evening prior to Thanksgiving followed by a dessert social. The church provides the ice cream and the folks bring other desserts. The service itself is a mix of prayers of thanks, reading of Scripture, singing, and special music.