Luffy vs BB: BB Takes away his powers, at least temporarily, and shoots him, Luffy is down, trapped in a structure made of pure darkness, where Teach can transform at will and Teach laughs as Luffy bleeds, but Luffy laughs too, blows away his darkness with a Haki burst, finishing him off with a regular-ass punch to the gut, or something else crazy.
Koby vs Kuzan: The two of them just absolutely box each other 1-on-1, Kuzan's beating him down, gets him frozen up, Koby laughs, then whips out his COC or whatever to win.
Sanji vs Shiryu: More invisibility vs Sanji... sigh. Draws on the themes of imprisonment in Sanji's life, and a stealthy(Stealth Black), Nazi-looking guy(Germa), in black(Raid Suit) who turns invisible(Special Ability) is kind of the way his life could've gone. Furthermore, Shiryu has a storm theme, and Sanji's using fire. Plus, imagine at the start of the fight, Sanji's like "want a light?" and then kicks the front of his cigar to light it on fire. Shiryu does some wacky shit to mess up his senses, laughs as he torments him, but Sanji also laughs, then just straight up murders him with some AOE shit. The fruit goes to a nearby tree, but he chooses not to take it.
Jinbe vs Burgess: Starts as a melee/wrestling match between the two, but Jinbe uses his tactics, skills, and powers to outplay his opponent's strength. Burgess has him pinned, goes to punch, and laughs, but Jinbe laughs too, then does some goated Jinbe shit, uses some advanced stance, turns his strength against him, and wipes him off the map with some new Fishman move.
Usopp vs Van Augur: They're on a group of rock-based islands in the ocean, Van Augur's teleporting around on some rocks, Usopp accidentally blows up one of his Pop Green things in his face, temporarily blinding himself, then starts shooting pieces of ammunition, seemingly chosen at random, at the rocks as Augur teleports place-to-place, eyes closed, predicting where he lands ahead of time, despite Augur using a nonlinear method of motion, seemingly random as well, to avoid the attacks, each of which poses a serious threat to him. When there's only one left, Augur appears, crouched, behind Usopp, gun to his head, and laughs, talking about how Usopp was a worthy opponent and such, and Usopp laughs. Augur pulls the trigger, and the gun explodes. Usopp planted a Pop Green in his own hair with that powder beforehand, and a vine's been creeping up the gun barrel since it made contact. Augur tries to get away, but every bit of nearby land is either destroyed or trapped, and he plummets into the sea.
Chopper vs Doc Q: They're slinging diseases and cures at each other, until, at one point, Brain Point, Monster Point, or Awakened Chopper lands a hit that slams something into Doc Q's face, knocking him to the ground, where he's sitting there, broken. All of a sudden, Doc Q looks around, and laughs. Chopper laughs too, and Doc Q looks at his body. He's not sick anymore. Chopper cured his incurable disease, proving he can cure anything, and as such, Doc Q has lost the fight.
Now, you may be saying "But SlendVeny, there's still 5 Blackbeard Pirates and 4 Straw Hats!" No. Either Vivi, a character won in a possible Davy Back fight, or someone else shall arrive. However, I have 2 matchups we need imo.
First, Brook vs Laffitte. Iirc, Laffitte is named for a pirate who faked his death. There's a theory that Laffitte's a former Rocks Pirate who faked his death and took a new identity. If he hasn't aged in that long, there's a chance he doesn't age normally, possibly due to his DF, which I believe to be angel-related. If he is that old, I want Brook to recognize him from back in the day(Maybe he faked his death twice. If Oda gets high off his ass, he might make him Yorki). No idea how Laffitte would fight.
Next, I cannot express enough how much more devoted I am getting to my Kaijuu Crusher Franky theory. Imagine that shit tussling 1v1 vs Wolf or Pizzarro.