From RainyDayColours on Etsy. This handmade stationery set includes four handmade kraft notecards with rainbow heart bunting flag sewn across. These cards are perfect for love notes, birthday wishes and thank you cards.
Make a flag line from your scrap papers, cutting each one like a small banner. Secure the end of the line with buttons. The card front can be several layers as seen here, or layers and colors of your choice. This one is a colorful handmade birthday card.
Card by Maile Belles includes tutorial on making buttons and button cards [Papertrey Ink (dies) Button Card Collection, Buttoned Up Buttoned Up (paper) Clearly Creative acetate Cardstock; (stamps) Button Boutique set, Button Up set]