1.so6p(no reason to explain)
2.tobi(6 bijuu and rinnegan , gedo mezo)
3.nagato/madara(the perfect rinnegan user and the ultimate uchiha , both could take on 5 kages)
4.nagato/madara(the perfect rinnegan user and the ultimate uchiha , both could take on 5 kages)
5.naruto/kabuto/sasuke(naruto and sasuke definately strong , kabuto has edo tensei... nuff said)
6.naruto/kabuto/sasuke(naruto and sasuke definately strong , kabuto has edo tensei... nuff said)
7.naruto/kabuto/sasuke(naruto and sasuke definately strong , kabuto has edo tensei... nuff said)
8.muu(jinton , invisibility , able to fly , not necessarily strongest by jutsu , but so tough to fight i ranked him 8th)
9.3rd raikage(10k vs him , he lasted 3 days and nights , can take on the 8 tails / gyuuki)
10.2nd mizukage(best genjutsu user of the old kage , can turn into steam and is capable of becoming intangable(turning into water)also has steam clones etc.)
11.minato(ftg , space time ninjutsu mastery)
12.hashirama(wood style , really fast and could control bijuu)
13.bee(perfect jinchuuriki)
14.jiraiya/itachi(best genjutsu user and best senjutsu user)
15.the other one(best genjutsu user and best senjutsu user)
dont criticise , this is opinion based , and also i havent added hiruzen , tobirama , izuna etc. cus their abilities are unknown