Not entirely sure how to go about tagging it, but this appears to be commissioned work of MMO PCs? So far I have...

小鳥遊 - girl on the left (PSO2).
...I don't have machine-readable kanji for the one in the middle but she's depicted - https://skeb.jp/works/24343 - here.
...I have no idea who the last one is on the right.

Rynol said:

Not entirely sure how to go about tagging it, but this appears to be commissioned work of MMO PCs? So far I have...

小鳥遊 - girl on the left (PSO2).
...I don't have machine-readable kanji for the one in the middle but she's depicted - https://skeb.jp/works/24343 - here.
...I have no idea who the last one is on the right.

Yeah, they're all original characters. 小鳥遊 雫 (takanashi shizuku?) is the name of the creator who commissioned the artist.

The two on the left at least are PSO2 PCs. The one on the right looks like it was created in Custom Maid 3D or something. https://twitter.com/ypsiwhm/status/1224093291324440577

e: oh it's some app called custom cast.