One Piece is a relatively aged, but still ongoing, manga written by auteur Eiichiro Oda. It centers around the seemingly outlandish concept that Monkey D. Luffy, a young pirate wannabe, eats a magical fruit that grants him the physical properties of rubber as a superpower, but at the cost of being able to swim. He is not deterred however and the series centers around his journey and quest to become the Pirate King, collecting a ragtag and diverse group of friends for his crew along the way.
Any fans of Dragonball will find themselves right at home here: One Piece is filled with little sight gags and silly happenstance, despite the adventure at its core. It does tend to have fights and battles, however I honestly have a lot of difficulty following most of them due to Oda's tendency to be a bit too detailed and fill-y on the panels. They don't tend to be very tactical, or have interesting gimmicks, but they are serviceable I suppose and Oda comes up with some really eye-catching designs and vivid personalities for our heroes to encounter (either as foes… or friends!) It has one of the most consistent and well-built worlds in a shonen demographic adventure series too, I feel.
There was an anime dub a while back, that aired on Toonami, and it's quite silly if you're interested in kitsch. Other than that the anime isn't very well done and its media (like music) isn't really worth checking out unless you're a hardcore fan. It's fairly cheap and poorly done, for par for this genre
You might find yourself overwhelmed by the sheer amount of chapters, but it's not as hard to get through if you put aside a few months.