Realized that lots of fast food chains have a signature beverage and there’s very little overlap:

Taco Bell - Baja Blast
McDonald’s - Coca-Cola
Cane’s / Chick-Fil-A - Lemonade
Burger King - Coke Icee
Wendy’s - Frosty
Whataburger - Dr Pepper
Taco Bueno - Strawberry Fanta
Subway - Cookie