From favorite to least favorite:
1) Kuma: arguably the best design in One Piece, one of the smartest concepts of a fruit, memorable role so far. Is virtually perfect.
2) Jinbe: very good design and a brave yet organic addition to the crew, adding a maturity that I personally enjoy, and everything about his praise of his new crewmates plus his relationship with Luffy is just very wholesome. If Bartolomeo is the childish fan, Jinbe is the smart and educated one, I can tell you!
3) Doflamingo: leader of my favorite pirate crew alongside the Big Mom Pirates, very nice design (especially as a whole with his officers) and one of the most memorable villains (although Dressrosa was a letdown for me).
4) Crocodile: can't say much, he was an iconic villain and it was interesting to see as an ally. The dehydrating power of the Suna Suna is still one of the most attractive usages of a fruit Oda has come up with, in my opinion.
5) Teach: I enjoy Blackbeard, but his time as a Shichibukai was pretty brief although it was a smart move on his part.
6) Moria: I like his design pretty much, his fruit while cool was underused (yet the concept of "shadow zombies" was interesting), and while some may hate his laziness I think he represented pretty well what Luffy could have turned into.
7) Mihawk: he just stands there doing nothing throughout the plot. Okay design, but I'm not the biggest fan of swordsmen.
8) Buggy: I actually don't enjoy this character too much, honestly. His humour is way too over-the-top for me to like him.
9) Law: edgy to the point of annoying and absurdly popular for what he's, but has a nice fruit.
10) Weevil: he's there and that's it. No feelings toward him, apart from disliking the idea of a subplot about Whitebeard's true or fake son; I don't really care and right now feels to me like beating a dead horse, or a plot this story didn't need.
11) Hancock: can't stand her in any way, I see her no better than the Celestial Dragons, the "loving Luffy" subplot always felt cringy to me, the connection between women, China and snakes is cliché as hell and her devil fruit, while interesting in its reference to Medusa, is again just the expected "lust power" too many fiction women have.
I think I didn't forget anybody.