There have been a lot of good ideas in this thread, and some that I think are spot on. I think almost everyone believes that Deku’s quirks will give him a broad foundation rather than making him an all out attacker.
One quirk I believe Deku may get is based off of Spider-man one of Horikoshi's favorite superheroes.
An sixth sense quirk something that allows Deku to sense the world around him like Spider-man's spider-sense, the supercharged version of this quirk could allow Deku to sense things at greater distance. The drawback to this quirk would be mental fatigue.
I believe that a quirk like this is almost certain to happen.
It’s also clear that Horikoshi used his characters names, and designs to make it clear what kind of quirk they have so I think maybe we can try and look at the designs to see who might have what.
Looking at the 6th user, the short, dark haired Jeanist clone. It seems like he is likely to have a technical quirk rather than one based on attack, defense, mobility, etc.
So I think Horikoshi could give him the spider sense quirk. He may even be cheesy enough to do something like this.
Name: 感読六太 (Rokuta Kantou)
Quirk: 第六感 (Sixth Sense)
Can sense the emotions of X people in a range of Y. Emotions could be things like. Distress/pain, intent to attack, nervousness, lying, sadness, etc.
this would be an amazingly useful quirk.
Its hard to come up with ideas for the previous users quirks , but i came up with two by looking up popular superheros...
For nana I think her original quirk worked kinda like photosynthesis. She would absorbs light into her body and give that energy to living beings by touching them with her hands. Things like makings plants grow, maybe healing people idk...
I think this quirk fit’s Nana’s design and name perfectly especially as one of the Kanji in her name,菜, means vegetable.
Basically, like you’re saying she should be able to transmit energy to living things to heal them, increase their power, or make them grow in the case of plants. Basically, she’d be Hashirama Senju.
I don’t want to speculate on the shadowed OFA figures, so that just leaves the large scarred man.
The fact that he has a scar like that, and his overall design indicate that he probably goes in for close range combat, and probably doesn’t have a defensive quirk.
I would actually like to see a mobility quirk that doubles as a leg based offensive quirk on this guy. Something kind of like Iida’s engine.
Maybe leg based plasma control that allows for enhanced ground based movement, advanced, complex, and more powerful kicking techniques that could supplement shoot style, and limited flight.