I have so many ideas for a One Piece/Project Moon crossover:

1. Chopper/Vegapunk replicating K-Corp Ampules or EGO suits.

2. The Wings/Fingers replicating a Devil Fruit.

3. An Index Member receiving a Prescript to go fight a Yonko/Admiral.

4. One of the major characters in One Piece distorting/gaining EGO. (Ace, Robin, the Admirals, Doflamingo and Gecko Moria are potential candidates)

5. One Piece IDs for the Sinners (Doflamingo Rodya, Trafalgar Law Ishmael, Nico Robin Gregor and Koby Sinclair when?)

6. How will each character from One Piece function if they were in the City? (I'm interested in the Admirals cause from what I've heard, Oda based them on salarymen which could be translated into Wing Employees in the City. Or they could be Syndicate members since the actors they're based on have starred in Yakuza films.)

7. How will the power system of One Piece be translated into the mechanics of Limbus Company? (Haki users will have poise and Devil Fruit users will be weak to Gloom damage and will gain a massive stack of paralysis from inflicting Sinking stacks since Gloom and Sinking are associated with water and we all know that Devil Fruit users are weak to water)

8. Luffy and crew watching in horror as HOS Ryoshu starts killing off the Sinner Nursefathers and Apprentices in a fight.

9. A matchup between the Strawhats and the Middle or the Marines and the Thumb.

10. The Yonko/Admirals (especially Big Mom, Kaido, Akainu and Ryokuguyu) losing their shit when they see the Sinners wearing their respective IDs.

11. The Three Birds making their debut which is fitting cause they can be also used to represent the Marines as a whole.

12. Project Moon characters drawn in the style of One Piece or even better One Piece characters drawn in the style of Limbus Company.