Okay, so this is just a Challenge! Fic or a list of plots/ideas/prompts for inspiration that you can use for One Piece Fanfiction:
1. The Strawhat Pirates finds a little boy who looks like Ace and ate the Mera Mera no Mi on a deserted island.
2. The Strawhat Pirates go to an island that is hosting a fashion contest. All crew members are forced by Nami to wear awesome clothes and participate.
3. (Alternate Universe) Luffy is a new teacher at Grand Line Academy and he has to teach the notoriously bad class of trouble-makers. (Can be like GTO)
4. Luffy ate the Tama Tama no Mi (Tama from Tamashii/Soul) and hears the souls of people with broken dreams cry around him. He travels around the world to save them.
5. Ace died and Luffy is in pain. What if he never sent out the 3D2Y message and his nakama come to help him recover instead of Jinbe.
6. What if Luffy had an ex-girlfriend and she appeared on the Sunny-Go one day?
7. Sabo, thought to be dead, appeared at the Marineford War.
8. Ace and Luffy are assassins for the World Government and later meet with the Whitebeard Pirates.
9. Luffy knew Haki before he started his pirate career or before meeting Shanks.
10. (Alternate Universe) Luffy is cursed and began on a journey to be the best Cursebreaker in the world (which is set in a fairy-tale like land). Ex. Luffy can have a rubber curse, Zoro the curse to have green hair forever, Usopp has a curse like Pinocchio, Chopper has the curse of turning into a reindeer, etc.
11. Arlong's POV after Tiger dies and how he felt when he broke his promise with Fisher Tiger, who didn't want the pirates to harm humans, and killed Bellemere.
12. Luffy became a Revolutionary when he was little.
13. Roger didn't get a disease and was still alive.
14. Luffy, Ace, and Sabo became pirates together and were on the same crew.
15. What if they were too late to save Keimi at the Human Auction House and had to break into Mariejois to get her back?
16. What if Garp took advantage of Ace leaving Dawn Island to become a pirate and forced Luffy to become a marine?
17. What if Luffy was a marine and had to fight against his brother's friends and nakama?
18. (Alternate Universe) Luffy is the heir to a large yakuza group, but he doesn't want to inherit it despite Garp's wishes. He and Zoro, his bodyguard, leaves the group and runs away. Doesn't have to be yaoi.
19. (Drabbles Fic) Write drabbles based on one-word prompts that are related to weapons in One Piece. Can be in the weapon's POV or drabbles about unexpected situations. Ex. Wado Ichimonji's POV of the promise made between Kuina and Zoro; as for unexpected situation, it can be like Luffy finding Nami's old bo staff and using it expertly in a fight to the surprise of his crew(hey, the guy used iron pipes with Ace and Sabo when he was a little kid so he should be good at bo staffs)
20. One of the Strawhats gets an apprentice or follower/fan.
21. Luffy gets interested in Franky's ability to grow hair by pressing his nose down for three seconds. So interested that he asks the cyborg if he can use him as practice for cutting hair. Or you may use another Strawhat to style/cut Franky's hair.
22. What if Luffy has the same ability as Gol D. Roger, the ability to hear the voices of all things?
23. What if Rouge had twins instead? And Garp drops both of them at Dadan's?
24. (Alternate Universe) Luffy aims to be the best racer in the world. Can be like Mario Kart. Can have random car designs like a car that is basically an upside-down straw hat on wheels or the Sunny-Go car version or the Merry-Go car version, or just regular cars. Prix
25. What if Luffy had Mythical Zoan Devil Fruit ability? And that day where Sabo is shot by the Tenryuubito, Luffy saves him by changing into his Mythical Zoan form and caught the eye of the Tenryuubito, who now wants him? If you're feeling a bit sadistic, then you may turn Luffy into a slave. And later get the marines to force him to participate in the Marineford War and fight his brother's nakama and Sabo.
26. Ace's POV; write about his search for the answer to his long-asked question: Do I deserve to live? May start from his birth or the time where he first discovered that he was Roger's son to his death at Marineford.
27. What if all of them except Luffy lost their memory? Like the Filler Arc in the One Piece anime.
28. (Alternate Universe) Luffy opens up a Yorozuya (Freelancer) business.
29. Luffy's POV; write about his feelings of the letter 'x'. The X mark was the nakama symbol that they used in the Alabastia arc. Now it is the shape of his scar that Akainu gave him, forever reminding him of his loss (Ace's death).
30. Write a guidebook that one of the Strawhats creates. Ex. Sanji's Guide to Getting Ladies, Luffy's Guide to Becoming Pirate King, Nami's Guide to Get Rich, Franky's Guide to be a Super Hentai, or something like that. Add humor.
31. Write about the feelings of those left behind on the Strawhat's hometowns during the 2 Year Timeskip Arc. How they feel when the Strawhats are considered dead to the world due to the absence of news (which they probably don't feel that they died and still believe in them). Also, how they feel when they get the news that they are back after the Return to Shabaody Arc. Those left behind may include: Makino, Nojiko, Zeff, Zoro's sensei, Kaya, Usopp Pirates, Aokiji (for Robin?), Kureha, Franky House, Brook's hometown in West Blue (the elderly people's reaction to hearing that the Rumbar Pirates are still alive)
32. May or may not be Alternate Universe. Luffy, Ace, and whatever other DF user you choose are experiments (guinea pigs) in a laboratory. Scientists are trying to discover how to make humans into supernaturals or mutants. The government supports the research and kidnaps kids or pick up orphans to use for the experiment.
33. Sanji and Zoro are in a fight and Zoro accidentally slashes Luffy who was sleeping on the floor.
34. What if Koala (the slave that Fisher Tiger saves and brings back to her hometown on Foolshout Island) became a pirate and joins the Strawhats. And she later meets Jinbe on Fishman Island, who recognizes her as the girl on that very day Tiger dies.
35. What if the Strawhat Pirates find a Devil Fruit? Who will eat it or what will they do? Tell where/how they found the Devil Fruit.
36. What if Luffy accidentally ate another Devil Fruit and is on the verge of death? Can Chopper save him?
37. (Alternate Universe) All of the Strawhats are animals at a zoo. Luffy, the new animal fresh from the wild, inspires the others to break out of the cages and go back to their natural place.
38. What do the Strawhats do on rainy days when they're bored? Will Luffy really read a book this time?
39. Luffy reveals his genius while playing a strategy battle game. How else is he able to keep all his nakama through the fights? Of course, it's because he's smarter than he appears! (I'm really obsessed with the idea that Luffy is a genius.)
40. Luffy becomes a vegetarian… Wait, what? How the heck did that happen? Bet? Sick? Disease? Change of mind? Tired of eating too much meat? Chopper influence?
41. Luffy gets a cavity from eating too much and brushing too little.
42. Sanji's worst fear happened; there is no more food left. They are stuck on the ship in the middle of an ocean where no fish seems to be living in.
43. Franky uses the Coup-De-Bo to escape from a fleet of marines. They go too high and land on the moon where there's a bunch of spaceys… and Enel? And there is no cola on the moon to replenish their stock… So Franky has to make an electricity generator or they'll have to steal some lightning to get off the moon.
44. (Alternate Universe) Ace and Luffy sneak into a costume ball that is hosted by the Whitebeard Incorporation for food. Decide on pairings.
45. On an island, there is a doctor contest every ten years in which all doctors of the world try to participate in. Doctors include Chopper, Law, Hogback, Kureha, maybe Hiliuk's ghost, and any OC.
Really, all this comes out of boredom during school. If you like my ideas and want to use them, then please tell me. You don't have to credit if you don't want to; I'd just appreciate it if you inform me that you're using the idea.