A few interesting finds while I was browsing through the list of participating circles.
Nakuru Aitsuki × Sennzai - soleil de minuit
The 1st collaboration CD between female vocalists Aitsuki Nakuru and Sennzai.
One Hundred Wishes - Second Wish ~夜に煌めく碧玲の追憶~ (Yoru ni kirameku aoi rei no tsuioku)
A circle consisting of 8 regular members. This will be their 2nd vocal compilation album, with nighttime and songs with piano as the themes.
PsyGoRecords (TY-2 a.k.a. Framdoll) - MidnightMaiden
An instrumental compilation album with "gothic" as the theme.
何度でも死ねる (Nandodemo shi-neru)- 視聴覚表現作品集 遠い国 (Shichoukaku hyougen sakuhin-shuu Tooi Kuni)
This collection revolves around the idea of combining illustrations and music to evoke the ambience of a faraway land. Each participating composer is given a piece of illustration, and each composer composes a song based on the picture.
anemone - killing me softly
A relatively new circle started by vocalist Yikii and composer ninomiya tatsuki. They describe themselves as a "fairytale like music group".