This is a set of clothes or accessories for figures.
From the Good Smile Company website:
The popular Nendoroid More After Parts 01 are being rereleased! This set of parts includes cosplay parts to transform your favorite Nendoroid into either a devil or an angel. In addition, three different musical notes, a sun, moon and two star parts are all included in the set!
A special 60mm x 120mm stand is also included giving you more than enough space to display your favorite Nendoroids in a cuter way than ever before!
Note: Certain accessories may not fit correctly depending on the Nendoroid character design. Additionally, please note that Nendoroid figures are sold separately.