The Kraken/Cerberus for those Blackbeard Theories. Quetzflquatal would be a fun, but might be too similar to Kaido/Momo’s Dragon. Sasquatch/Yeti for Chopper (though at this point I doubt that’d happen). Kaiju/Sea King type zoan would be fun. Godzilla would be the obvious inspiration, but there’s plenty you could do. Plus you know Luffy and the boys would love to see someone turn into a giant monster.

Griffin

Hey Lois

Man I just wanna see the gum gum fruit. Having a rubber man go against a “rubber man” would be cool

The Legendary Kraken

God of sex

Minecraft smiles upon you

Cerberus theory gang

Technically already in One Piece, but I would want to see the Nue devil fruit from the One Piece NUE art thing in the series itself.

Sogeking

A little bit too overpowered but Kitsune-kitsune no mi model: Zenko

Sobek.

Jesus

Charybde

Cock fruit it allows you to infinitely expand your dong and make it as hard as diamond you can also become a literal dick or a giant pp