Re: 5 people who can beat Minato
FTG-allows him kill ninjas rainging from fodder to skilled jounin before they get to perform any jutsu to matching Kage level shinobi like A and B without receiving any sort of injury.
Space Time Barrier-allows him to counter attacks as large and fast as TBB.
Contract Seal-allows him to remove one's control over their summoning.
Eight Trigrams Seal-made up of two Four Symbols Seals and allows him to seal half of the Nine Tails(a bijuu which matched 5 others in power)
Four Symbols Seal-Just like Eight Trigrams Seal but most likely weaker but still stronger than the seal that holds the Eight Tails in Bee according to the jinchuuriki himself.
Dead Demon Consuming Seal-suicide move. Requires a bit of prep time. Can seal up to half of Kurama's power.
Can Sense opponents by placing finger on ground.
Body Flicker Technique-allowed him rescue Kushina from a Nine Tails attack. Allowed him run across Konoha and from the mountain to the outskirts before the Nine Tails could form a Bijuudama. Allowed him rescue baby Naruto from Obito's kunai attack which was already at point blank range.
Rasengan-A Rank move that could create a deep crater for Tobi and damaged the earth greatly when it hit the Uchiha.
Gamabunta can perform
Food Cart Destroyer Technique-strong enough to hold down the most powerful bijuu in existence.
Water Release: Water Gun-strong enough to match an attack from the weakest bijuu in existence.
Toad Oil Bullet-creates so much oil that when ignited by a fire technique, creates an attack that is second only to bijuudama in size.
Toad Beheading-high speed taijutsu move that could remove the limb of a bijuu before it could react.
Also, Minato would possibly possess the Combination Transformation where he can combine with Bunta to form anything.
The man has techniques that can overpower bijuu, being with the largest techniques in existence. Clearly, you can't beat him by just having a really big ninjutsu. He can either seal them, ST barrier them, teleport away from them or match them with his toads large ninjutsu. Have his toad jump over them.
You also can't sneak up on him since he can sense opponents by finger and also could sense Tobi approaching him from behind without finger.
You can't use fast attacks to kill him since his teleportation is faster.
You can't genjutsu him, at least not normal genjutsu, since he can summon Toad allies. So to beat Minato, you need attacks that are-
Bigger and more destructive than Nine Tail's Bijuudamas.
Faster than A.
And if genjutsu, it must be genjutsu that can't be broken by someone else flowing chakra into him.
Well, there's Rikudou(whoever says anybody can beat Rikudou needs to seriously reconsider their position on this)
Obito with his Six Bijuu(still debatable especially since he can turn bijuudama's back at them, when Naruto fought the Nine Tails, he used a Rasenshuriken to make the Nine Tails unable to stand up, even the great Kurama was weakened by a Rasenshuriken, imagine what will happen if any of Tobi's bijuu, which are weaker than Kurama, receive a TBB. They could die..if that's possible or so greatly weakened that Minato can seal them. As for their combined Bijuudama, I doubt it has more chakra than the half of the Nine Tails Minato easily sealed with the Eight Trigrams Seal so he can seal it or place a marking on one of them before the fight progresses to that stage then teleport home and then teleport back to the marking. I still give Obito since Minato most likely doesn't have the chakra levels for such a prolonged battle.)
Edo Madara(grrr.....Mokuton can be countered by ST barrier and Bunta leaping over it and using oil+explosive tags to burn Mokuton flowers but then there's the Perfect Susanoo which can crush mountains with a sword swing. Minato may not be able to get close enough. There's also Shinra Tensei which will make sure of that. Susanoo clones are easy; mark the Susanoo then teleport around them, they can't get him. Then go for real Madara. Fire Techs aint as big as Bunta's water or Minato's ST barrier. Grrrr....if Minato can somehow get the Toad Sages to genjutsu him, he can seal him with Eight Trigrams Seal. Or if Minato were somehow an Edo or had a bijuu to constantly fuel him with chakra and FULL KNOWLEDGE..the Yellow Flash stands a chance but as it is Madara is above him.)
Naruto's speed is most likely above Minato's reflexes so he'll win. If not, then Minato wins as he has sealed the Kyubi before.
Hashirama is debatable as Minato can ride Bunta and have the toad leap over Mokuton and incinerate Flowers with oil+explosives, can summon a small toad to break him out of Genjutsu: Bringer of darkness. But Hashirama's clones and their ability to merge with wood will make it difficult to get Hashirama before his chakra runs out though Jiraiya did once mention that toads can sense an opponent by smell(when he went to search for Tsunade and gave Naruto his bag, he told Naruto that if he gets lost, Toads can track him by scent). Minato's best shot is the great Sages' genjutsu. Still very very debatable.)
Itachi(Itachi's only real shot is genjutsu since neither Amaterasu nor Susanoo are bigger than bijuudamas nor faster than A) However, considering how well informed Minato is about the Uchiha such that he knew the intricacies of Tobi's control over Kurama combined with the fact that he has never flashed back to Tobi and remembered his Sharingan in his mask, meaning he didn't see that that night which could only mean he wasn't looking at it as he and Tobi came really really really really close to each other;face to face, Minato won't look at his Sharingan and as for non eye contact genjutsu, Minato is a genius, no recorded genius in Naruto, with the exception of Neji, has had below a 3 in genjutsu. Considering that Minato, unlike Neji, isn't a taijutsu type but is well rounded as a ninja hemost likely has 3 or higher in genjutsu which is enough skill to break non eye contact genjutsu as seen when Guy who has 3 in genjutsu broke Kabuto's A Rank genjutsu which put everyone in the Chunnin Exams to sleep)