This is a 1980s style leotard lovers dream lot. All 12 are new without tags (never worn). 
Brands include:
One Baltog has the brand tag removed. Another doesn't show the brand (see pictures).

Capezio (American Ballet Theatre-ABT) and George Van are a large but will fit a medium.

The long sleeve bodysuit does not have a brand. One leotard does not have labels.

These have been in storage for a number of years.