Those are green-teal stencils.
Teal With Black Edge Alphabet Icons
This is a set of printable letters which are teal with a thick black edge design. The letters have a transparent background – perfect for adding some color and elegance to your projects! Use this set to create banners and bunting spelling out different words, or add the letters to the front of handmade cards or scrapbook pages to personalize them. All 26 letters are included individually as separate png files, plus ñ and punctuation. These are combined into a single zip file.
These are large files – you will get great quality prints on letter/A4 paper.