I think... Nagato Uzumaki and Naruto Uzumaki are the strongest Duo.
Nagato is just a Muafuckin' Beast, and so is Naruto.
Naruto could give Nagato chakra whenever he wants, which would overpower anybody.
Some Ultimate Move Possibilities.
Nagato could provide Protection and offense as Naruto provides Support and offense.
Tell me who could possibly beat this team?
If you can't tell me another good team.
P.S: I know you guys will resort to something including Hashirama or Madara since nobody else could match Nagato and Naruto's combined strength.
P.S.S: This is just how powerful Naruto would be with Rinnegan. :D