Viz’s One Piece Box Sets contain 20-24 Volumes of One Piece Manga, as well as a Poster and a Special Booklet.
Box Set 1 contains the Romance Dawn ver. 1 one-shot complete with redrawn SFX.
Box Set 2 contains the Strong World Chapter, also known as Chapter 0 or 565.5. It is a tie-in to the movie One Piece Film: Strong World, but it’s actually entirely canon.
Box Set 3 contains two special chapters. A One Piece X Toriko crossover and a One Piece x Dragon Ball crossover.
Box Set 4 simply has a collection of the Jimbei cover story and isn’t anything special. I haven’t included it in here.
The booklets have been scanned myself in 2400pixels. I’m not the best at cleanup but I did my best and I think the result is serviceable.
The One Piece x Dragon Ball crossover I didn’t actually scan myself. I found some uncleaned scans on nyaa.si of the WSJ issue and used that. The pages are larger and the color pages are actually in color.
The One Piece x Toriko crossover I didn’t use any scans at all. It was on Viz’s official site so it’s just ripped straight from there. It’s lower resolution but much cleaner quality.