Seller: Tina feng store on Aliexpress.
These are official Hasbro licensed merchandise made by PMI Ltd, an Israeli company that specializes in licensed kids activities and stuff. The paint job on this lot is a bit irregular, so they could be factory seconds.
Each stamper has a screw-off cover. They are pre-inked but don’t have an ink pad.
My assortment was heavy on Rainbow Dash, but I got at least one of each character in the listing photographs.
Rainbow Dash, 3 poses:
Fluttershy, 2 poses:
Rarity, 2 poses:
DJ Pon-3 and Pinkie Pie:
Celestia, Cadance, Shining Armor: