I can't choose they're all good and have their place I feel - though I know which one I DON'T like and that's the "completely serious and dark, no redemption or sympathetic qualities' type of villain such as Jadiete and 90's Rubeus. Such villains I find are boring and one note (at least the always evil but goofy ones like Germatoid are fun) and feel little more than upgraded MOTD, a large part of what makes the 90's anime so appealing in the first place is how fleshed out and humanized the villains are relative to their Manga counterparts (For the most part ---- looking at YOU 90's Beryl and Galaxia) If I wanted "purely evil for the sake of being evil" villains then I would read the Manga.
Also can't decide. I really do love it when the villains work together as a team and are close such as the majority of the BMC (barring Rubeus & Esmeraude with each other), Kunzite & Zoicite being a couple, the Amazon Trio, the Quartet, Siren and Crow etc - but I also really appreciated the petty, dirty politics going down between Nephrite and Zoisite's rivarly which implicated some pretty interesting history between them. On the whole I would say I prefer when the villains have good relations more often than not as the only time when the tension and backstabbing was interesting was during Classic with Nephrite vs Zoisite and a little bit of Kunzite vs Evil Endymion. By the time S rolled around and each Witch was one-upping and betraying the other it just got trite and uninteresting - basically if they're gonna attempt to have "office drama" between the villains as coworkers, there's a
way to do it and make it intriguing and everything post Dark Kingdom wasn't it.
Aww I loved the Ayakashi Sisters! They're easily one of the best parts of R and I would say one of the anime's redemption examples that was more than well earned. (They barely did anything bad and never went after civilians unlike literally every other villain who got redeemed save for Saphir - worst they did was attempt to kidnap a kid but she was an important political figure and barganing chip being the daughter of the rulers they were at War with so she doesn't even technically "count" as a civilian)
I admit they could've laid off the Over The Top misogynistic stereotypes of them being catty, boy-crazy mean girls attempting to compete with another over the affection and approval of one man, but hey basically all the Inners were flanderized that way as well - I just chalk it up to the 90's anime being mostly written by old men in suits who are writing based off of old-fasioned, sexist tropes/beliefs what they
think women are like, rather than what they
actually are. At least each sister has their own unique, distinctive personality that's easy to relate to - Koan is impulsive and in love but naive and gets led on/toyed around with and her heart broken, Berthier is a sweet seemingly ditzy airhead who's actually a genius, Calaveras is a shrewd businesswoman and Petz is prideful, bitter and uptight.
I've yet to see whichever Musical she's from but please dont' tell me that's actually her real name and not just an unfortunate, subtitled spelling?
Which is why Manga Galaxia is so good a villain as she is. She's completely menacing, dark, effiecient, smart, complex and very sympathetic - yet even she realized in her ephipany that there was no going back after what she did and in order to obtain redemption she had to die.
You don't think Fish-Eye or even the anime-only Fiore and Ail & En had good redemptions?
Nephrite's was written well with nuance but 90's Demande's was a bit rushed - the old Musical version of him is better in this regard. Still a vastly better person than his Manga/Crystal counterpart either way but the bar is so low set there that's barely an accomplishment.
To be fair to Nephrite, it remains ambiguous what the nature of his feelings for Naru even where. He very well might not have returned her romantic feelings but just came to care for her platonically as a friend. The way it was
written was creepy, but we don't know for sure if Nephrite's intentions were. (This is why I always like to say 90's Nephrite would've been better served by being aged down to Ail's age and simply going undercover as a Senpai in Juban Middle School instead)