They are available at https://ko-fi.com/buyeuropean/shop

For example: 10 stickers of 9,5 cm € 4 / 25 stickers of 4,5 cm € 4 / 50 stickers of 9,5 cm €12 / 100 stickers of 4,5 cm €14 / 100 stickers of 9,5 cm € 20 / (excl. shipping)