Car mechanics, dealerships, house fixing contractors, city (property taxes), these are the ones that I can think of in the past year I've come across charging a fee for credit card payments. What's most irritating is that most of them do not setup for and drop the fee if you pay by debit card.
Always ask if they’ll give you the discount paying with Zelle if they won’t for debit. Almost every major bank supports Zelle currently in your native banking app.
https://www.zelle.com/get-started