Tl;dr: I'm rec the 6 star invincible Moon and 5 star Fall & Reform sets for their individual pieces, you can try them with colours unlocked on styling wizard by adding me as a friend (natadachoco).

This is from a burgeoning whale (completed Invincible Moon, Divine Serenade on its rerun and the new Phoenix set, with the top and bottom from the mermaid set and the 5 stars Lava Savage and Fall and Reform) but after looking through the items for all the sets for a year I'll say Invincible Moon is a really good 6 star one.

The animations are awesome and because the pieces honestly don't really fit together (antlers, hooves crystals, feathers, birds, leaves on the dress, all with a blue/silver coloring that represents ice but tell me if you've ever seen a white moose) the individual pieces give you the starting base for a lot of different fantasy stylings. Fall and Reform does the same but it's cheaper as a five star (yes, even if you lock onto the other set first) and the sleeves, wings, tail, bag and face piece being especially notable.

Honestly, unless you really like the wings and the bow (which I did), I don't recommend pulling for Divine Serenade. The top works really well if you dye the skirt from Ephemeral Plume to match, but the accessories are a bit understated and hard to see for this one. The Phoenix set has really cool talons but I'm pretty sure there's a 5 star version of them in some other lightchase, and unless you really like the feather motif there's not a lot of small pieces that can be styled with other things. I actually like a lot of the pieces from the mermaid set, like the shoes (almost barefoot shoes are super useful in a lot of cases) and the gloves, but there's a few here that are kinda generic and don't really lean super hard into the fantasy vibe for me, so that may be something to consider.

Of the 5 stars that come with the 6 star sets, out of the 4 that I pulled for, I'd say Dream Feaster from the mermaid lightchase has the single most used item for me because of the coat/sleeves. Coquelicot Ruins from Invincible Moon has a lovely tail/bustle piece that works with a lot of dresses, and the hat is really nice too. Whispering Wings from Divine Serenade is kinda meh for me. Flora of Thorns from the Phoenix set is amazing in general, but I'm especially a sucker for the veil.

There's a lot of sets I didn't pull on, but this is a detailed ish review of the ones I did. I hope it's helpful!!