Amazon.com: Grafix Medium Weight Acid-Free 0.057” Chipboard Sheets, Create Three-Dimensional Embellishments for Cards, Papercrafts, Mixed Media, Home Décor, and More, 12 x 12, Natural, 25 Count : Everything Else
Amazon.co.jp: White House Double-Sided White Cardboard (Chip Ball), 12.2 x 8.7 inches (310 x 220 mm), Slightly Larger Than A4, Approx. 0.08 inches (2 mm) Thick, Set of 5, A4, No. 26 (1.92 mm) Thick) : Hobbies
Amazon.com: 7mm Black EVA Foam Sheets for Crafts, Cosplay Costumes (9.6 x 9.6 in, 10 Pack) : Arts, Crafts & Sewing