Originally Posted by FriendlyFacez

Is there a list or an existing thread that ranks the top 6-star characters in order of ability or power level? Probably won't drastically change my 6-star ticket selections (there are certain characters like Dendrobium I won't take regardless of their merits just based on design preferences) but I'd want to at least avoid selecting a few of the least powerful / useful 6-stars.

It's really hard to say, since some girls have a bloomed form, but most don't, several of which don't even have a Bloomed form on DMM yet. And that matters quite a lot.

For example, Cactace is relatively weak for a rainbow. Yet, on DMM she got a bloomed form (and no idea when we'll get that here, since Nutaku doesn't follow the same release order for bloomed girls), and she turned from one of the weakest rainbows into one of the most overpowered ones.
On the other hand, Sakura got a nice bloomed form as well, but that wasn't half as big an improvement as the one Cactace received. The two are much more closely matched in their bloomed forms.

So in the end, the best advice is, and will always be: pick your waifu, or if you already have your waifu, pick a concubine to go with her. Ampy her up like there's no tomorrow, get her a nice skillbloom every month, and she'll be good. And next time you get a ticket, go through this list and find her a nice team member with matching (often the same!) passives.

Trigger-rate girls match well with other trigger-rate girls, debuff girls go well with other debuff girls and somewhat with +DEF girls, countergirls go very well with oother countergirls, evade-girls with evade-girls, etcetera.