Joltik for C rank for sure. Its a very good scarfer but a bit outclassed by Chinchou and its SR weak. It can scout well when SR isnt on the field and its pretty good at revenging.
Drifloon for high B rank or low A rank. Its flying gem boosted acrobatics just OHKO's nearly everything that doesnt resist it. And after that you can blast your opponent away with more acrobatics, shadow balls and hidden powers. And the speed boost unburden gives you nearly always make you move first. And with a really fast destiny bond you can take your opponents with you. If played right this cute balloon can atleast destroy two pokemon on your opponents team.