Shinsekai is a minimal outfit, created for Aiko 3 by outoftouch and Bobbie25. It is not free; one can purchase a copy from DAZ3D.

Shinsekai
Download Links
Main Site:https://www.daz3d.com/shinsekai/ non-free content
Other Information
Creator:outoftouch , Bobbie25
License:Daz Productions, Inc. End User License Agreement
Needed:Aiko 3

Free resources for Shinsekai include:
Fashion Styles for Shinsekai A3
https://www.sharecg.com/v/34891/