Limiting it to one room is a bit difficult for me. TheDuke55 is onto something with their suggestion of the Pascal items though. LambdaDelta as well with their recommendation of the wallpaper and flooring. Maybe a
Bill Blaster would fit in too?
I can definitely see a
Straw Hat item sitting underneath a
Jolly Roger that's hanging on the back wall of a room. Another good general One Piece item would be a
Snail Clock as a reference to the Den-Den Mushi communicator snails. Maybe a
Mermaid Statue and/or a
Model Sailor because of the Straw Hats befriending the Fishmen. Maybe a
Top Hat as a reference to Sabo?
My brain instead focuses more on creating villagers/rooms based on characters from the series, though which ones you'd choose would be up to your own discretion of course.
I can see Nami being a good choice for that. Because of her fondness for treasure, a room adorned with
Aluminum Briefcases, a
Cash Tray,
Hyrulean Treasure,
Mountains of Money, a
Piggy Bank, some
Piles of Cash, a
Ring,
Sacks of Money, some
Safes,
Treasure Chests, fancy dresses/clothes on mannequins and maybe even a
Hanger Rack. I can also see her having a
Jewelry Case. Since she's the navigator, other good items include a
compass (though the
Ship Compass from the previously mentioned Pascal set of items might make that redundant) and a
Desert Island Map and/or a
World Map.
Sanji's a good contender as well as there are plenty of items related to cooking, food, and the kitchen. I especially like the
Cutting-Board Set and
Pot Rack for him. There's even a
Menu Chalkboard. I can definitely see having things like the
Barbecue Spit and
Roasted Dino Meat because Luffy's been shown to eat that sort of thing before. There are a bunch of choices or the kitchen stuff though, so I invite you to
give the list of items a look for yourself. He might also benefit from a
Box of Tissues considering his nosebleeds.
Likewise, for Robin, there are a number of items related to books like the
Book Stand, the
Heavy Tome, the
Homework Set, the
Instruction Manual,
the Large Bookshelf, the
Large File Cabinet or
Medium File Cabinet, the
Stack of Books, and the
Strapped Books. She could also do with cute items like the
Cloud-Making Machine, one or more of the
Lucky Cat items and/or a
Nabiru Ornament,
Poogie, a
Snow Bunny, and/or one or more of the
Teddy Bear items since she has been shown to have a weakness for adorable things.
There are a number of items that relate to Chopper's role as the crew's doctor, like the
Boston Bag,
First-Aid Kit, the
Hospital Bed, the
IV Drip, the
Medicine Cabinet, the
Medicine Chest, or a
Modern Hospital Bed. Additionally, his Rumble Balls can be referenced with something like the
Candy Jar,
Candy Machine, or
Capsule-Toy Machine.
Brook? A
Milk Carton and/or
Lon Lon Milk, a
Mic Stand or
Silver Mic, and a number of musical instruments like the
Double-Neck Guitar,
Electric Guitar,
Metal Guitar,
Rock Guitar, the
Synthesizer,
Violin or other similar
String Instrument. Also, maybe a
Skeleton Figure because why not?
Franky has a few potential items like the
Robot Hero since it's similar to his General Franky, the
Drink Machine, the
Soda Case, and
Soda Fountain. Since he's the shipwright he could also have items to do with building and maintenance like the
Carpentry Set,
Tool Shelf, and
Tool Stand. Along that same line of thought, he might do well with a
Sailboat Model and/or
Ship in a Bottle.
Zoro's kind of difficult to come up with stuff for other than a
Barbell,
Black Katana,
Ninja Sword,
Sandbag,
Sword,
Weight Bench, and
White Katana since he has been shown to lift heavy weights and he fights with the swords.
Usopp? How about one of the
Slingshot items and a pair of
Goggles or a
Pilot's Cap.
I'd probably recommend having multiple rooms instead of relegating it to one room, but you could also mix and match items from the sort of things I've listed that might represent certain characters and see how that works. If you wanted an animal resident who might represent something from the show, Agent S kind of strikes me as a good representation of the Navy characters.