Cannon!Guy is 100% S ranked. He very nearly punched Madara to death.
While reading the wiki, and accepting what google told me was a list of S rankers, I found someone interesting:
Chiyo. First thing, old ninja, so be terrified. Second, she has the most bonkers diverse skill set.
- Skilled enough at sealing to put the tailed beast into Gaara (So not as good as Minato or Jiraiya, because Gaara's seal is messed up, according to cannon)
- Puppet Expert
- Poison expert
- Med nin
- Genjutsu
- Strong enough to survive direct confrontations with Hanzo, who only died to all three sannin.