This is a set of clothes or accessories for figures.
From the Good Smile Company website:
The popular Nendoroid More After Parts 02 are being rereleased! This set of parts includes cosplay parts to dress up your favorite Nendoroid in a cat or bunny costume! In addition, two cats and three butterflies 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 Nendoroid 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.