If you are talking about burgers...
Burger King
I never really cared for burgers back when I was still eating meat. I was the person who always chose hotdogs over burgers at a BBQ. I also hated the McD burgers. HOWEVER, Burger King Whopper Jr. was the one burger I did enjoy. They also now have Impossible Whoppers so I can still have them now that I can not eat red meat. There is also something deeply nostalgic about them, to bad there are not a lot of Burger Kings in my area.
When it comes to chicken sandwiches...
Wendys
Too bad I can't eat them anymore, they were really good. So much better than Chick-fil-A.
Everything else...
McDonalds
Even tho I hate their burgers and chicken, I think they have really good breakfast items (RIP all day breakfast). Their ice coffee is really good, I prefer it over Dunkin or Starbucks. Meat upsets my stomach so there isn't really a lot of sandwich items I can eat. However, the Filet-O-Fish tends to not make me ill. McD also has Grimace as well as other weird characters. And McD has that cartoon which is so amazingly weird.