Here's a listing of apples rated from sweet to tart, one being the sweetest.
5. Red Prince & Jonathan
6. Red Delicious
7. Honey Crisp
11. Pink Lady
12. Granny Smith
Haven't tried them all, but we like tart over sweet and usually buy the small dark green Granny Smiths.
Also like the Braeburns, if they're more green than red and have to be hard and firm, they seem to be a combo of sweet and tart.
Tried some Pink Ladys after seeing this list and they have a great unique mild tart and uniform flavor.