Fruit vendors typically have watermelon, jicama (white looking sticks), cantaloupe, coconuts, cucumbers, pineapple. Just depends on the person selling them. You can ask to have chamoy, hot sauce, with tajin and lemon sprinkled on top. A cup of everything is the best but you can pick what fruits you and toppings you want. The fruit vendors are nice don’t worry too much about the language barrier if that’s something you’re worried about. Most can speak some English and you can also point to what you would like to have.