Blah blah blah, I'm human (I think) that's all you need to know.
CHALLENGE 1 - (Hopefully for TheVictor or Animaninic Dude)
Time Travel one ( I know it's been done) But this time everyone dead (so post timeskip) ZORO gets sent back (all skills, knowledge slight strength boost and left eye not working properly, stills see just not well) and TWIST can pick ONE OTHER CREWMATE to regain the same has him BUT can NOT be Luffy. Take the challenge head on.
The strength boost is relative to the degree he can see with his busted eye (full vision, full time skip strength, no vision = no timeskip strength) his eye did get cut in the 2 years.
NOTE*
Whoever is 'reawakened' by Zoro unlocks all Haki (including King's) within themselves. No skill with it but unlocked.
CHALLENGE 2 - anyone
The ULTIMATE OC CHALLENGE
Still Luffy and classic straw hats (east blue only), but instead of heading to the Grand Line, they decide to go out and decimate the other 4 Blues first, to get stronger and basically make the marines look bad. New nakama acceptable, along with any craziness you think the other 4 blues should have. Enjoy!
OPTIONAL*
Try to incorporate my personal Logia fruit into the story somewhere - Logia of Knowledge.
CHALLENGE 3 - anyone
Water Control Paramecia (Logia is overdone) Luffy: Shanks takes Luffy to Grand Line, on the way to the New World Luffy meets Jimbei. Jimbei takes over caring for Luffy from Shanks and teaches Luffy Fishman Karate which is massively OP since he is made of water and Fishman Karate is all about water manipulation. Where it goes from that is up to you. Have fun.
Challenge 4-a - anyone
There are a few "Supernova Strawhat Pirates" stories out there, but one I haven't seen is this - Admiral Strawhats. Kuzan, Borsalino and Sakuzuki all become member of the Strawhat Pirates, that's the only requirement for this challenge. Of course considering who is now a straw hat chances are its going to turn into a straw hat fleet story as well. Have fun.
Challenge 4-b
On that note, you can do a variation where all the Warlords join Luffy's Crew, can happen before or after they become Warlords, up to you.
Challenge 5 - anyone
There is currently a fanfic out there called Ten Tailed Strawhat, read it and pick one of the one shots (some are two shots one is a three shot) in the story and base a full length fanfic around it. The Ten Demon Beasts from the Naruto Manga are introduced into the One Piece World as Mythical Zoans. Have fun.
P.S
PM me if you accept a challenge.
Currently dead Fanfics that I would like to see adopted:
1. To Every King, a Crown by T-Biggz. Summary: Luffy got goggles similar to Ozzy Osbourne, devil fruit changed to Float-Float, uses a Bo-Staff. No Straw Hat! For further details read the 4-6 Chapters already up.
2. One Piece : The Lottery Lottery Fruit by evelsaint93. Summary: Luffy ate a random-generating Devil Fruit and wound up as the next incarnation of the Sea God, Susanoo. Got mystic sword, shield and necklace.
3. The Boy with Haki by donalgraeme. Summary: What if Luffy discovered his Haki at a young age? Like, when Shanks was around. Watch as a stronger, smarter Luffy emerges to take the Grand Line by storm with the power of the King's Disposition. Warning, some content could be considered spoilers. LuNa - possibly not dead, will delete if updated.
4. The Straw Hat Armada by Watasumi. Summary: Benn convinces Shanks to take on Luffy as an apprentice. This one event causes many changes to the normal plot. Stronger Luffy but not OP.
5. One Piece: Rise of the Second Pirate King by TheDemonKingNaruto. Summary: Massively OP Luffy, still got Gum-Gum powers. Luffy & Nami reincarnated versions of Gol. D. Roger and Portgas. D. Rouge.
6. Second Round by Rasberry Jo. Summary: Sabo's life was saved by Dragon ten years ago. He, Ace and Luffy went to become pirates at age 17 and 14. What would happen with our beloved Straw Hat Pirates if they had a captain who already knew Grand Line?
7. The Second Tour: Uncut! by OneLastBird. Summary: And they enjoyed a new freedom hard won from the Tainted Coil. However, deep within their world stirred a force so terrible that even the Gods forbade its mention. The Black Host was about to rise again... There you go a sequel to Brutal Legend.