1. Subway - Cheap to own, and has a lot of locations inside things like hospitals or even office parks. Numbers are misleading.
2. McDonald’s - Yes.
3. Starbucks - Not fast food. Again, a lot of "mini-locations", but overpriced coffee and pre-made baked goods for the pretentious do not a restaurant make.
4. Dunkin - Bigger selection than Starbucks, but is a donut shop "fast food"?
5. Pizza Hut - table service at most locations. Made to order pizza, not fast food.
6. Burger King - yes
7. Taco Bell - Longtime Pepsico stockholder. Back when companies used to actually mail you an annual report, one year there was a line about "Taco Bell prides itself in the lowest food cost in the industry." Says all you need to know about the place.
8. Wendy’s - Yes.
9. Domino’s - Pizza delivery, which is mostly what Domino's is, is kind of a different category from "fast food".
10. DQ - DQ is big in off the beaten path places. It has some quirks that make the chain big. For one thing, back 50 or 60 years ago, they sold franchises for little to nothing and as long as mom and pop pay a small fee, they can keep it, often still simple walk up locations. For another, as I understand it, the food part was sold later and a lot of places either do not have food at all, or have their own food, in their own generic wrappers, selling only the franchised ice cream. Texas is like one big franchise with its own food that is different from the rest of the country. Outside Texas the company has been pushing for franchises to go to the "Grill and Chill" format, which is more like regular fast food, but there is no obligation to do so.