1.Vivi-I liked her interactions with the Straw Hats, especially Luffy and how they advised each other like when Luffy was being reckless about the Nami being sick situation and when Vivi was being too optimistic about the situation in Alabasta. Still wish she could've joined the crew but it's understandable that certain characters have duties to uphold despite their close bonds to the Straw Hats. She tried her best despite her flaws and it was really endearing.
2.Tashigi-I like her determination to advance and how she beats herself up over her shortcomings. At times her mindset that people are looking down on her for being a female might not be the best but I still root for her to improve and I liked her pre-timeskip and during Punk Hazard. I hope to see more of her interactions with the Straw Hats, especially Zoro since she's most familiar with him.
3.Reiju-I think she's the best Vinsmoke (aside from Sanji) and it was amazing of her to save Sanji and to encourage him when he was unsure about everything that was about to happen with the Vinsmoke assassination plot. Due to the circumstances she was in as a kid as well as due to Judge's orders, she went along with how Sanji was being treated but I like how she doesn't forgive herself for that and tries to help Sanji (both when he was a kid and during the events of Whole Cake Island).
4.Pudding-At times, I disliked her for her treatment of Sanji but it became clear she was warped by her mistreatment as a child and the lack of appreciation she was given from her family. The whole two sides to her thing is really interesting and she came off quite sympathetic to me by the end of the arc. It's also funny to me seeing a girl get a nosebleed over anytime Sanji does or says something remotely cool.
5.Nami-her seeking to become more useful in battle to assist Vivi and the crew was great in Alabasta and her saving Sanji, criticising his chivalry while also respecting him for it was a nice scene and he really needed that (also helps you see how close the Straw Hats are and that they can depend on each other). It's always great when Nami gets a fight to help those close to her (Vivi, Sanji or Tama). Even post-timeskip, Nami's still incredibly helpful to Luffy and the rest of the crew.
6.Robin-Robin's backstory was one of the saddest ones and helps you understand the importance of her dream, both to herself and to Luffy. I thought it was amazing when she finally put her faith in the crew and her admitting she wants to live made for one of the best moments of the story. Robin was really great in her entrance when she saved Sanji and hit Black Maria.
7.Vinsmoke Sora-Great mother and her eating and enjoying Sanji's food despite it tasting bad to show appreciation for his hard work was really touching. It's clear she made an impact in both Reiju and Sanji's lives through her love. We might've not seen much from her but taking those drugs to save Sanji from Judge's work was really admirable and her encouraging Sanji's work when he needed it the most (when practically everyone else was insulting him for it) left quite an impact.
8.Carrot-She still has a lot to learn and she seems to still be thinking about Pedro's words even up to now so we'll see how everything with her plays out. Her interactions with the Straw Hats are nice, whether it's hanging out with Chopper or telling Sanji that he shouldn't beat himself up over Pedro's death (showing that to an extent she understands it was a sacrifice to save the Straw Hats and that Pedro was content with it).
Koala, Bellemere and Kureha were great as well and Big Mom can be pretty good at times.