It's pretty common in Canada to be able to order fries with sour cream, green onion, tomatoes, and cheese/queso. (It's the best thing on taco bells menu and they don't even have it state-side)
That being said fries are way greasier than a baked potato, and they are better suited to more acidic condiments (ketchup, malt vinegar, etc)
Unironically my two favorite sauces for fries. I attribute a not insignificant portion of my weight gain pre-COVID on slathering cafeteria fries with too much mayo.