cork
https://www.amazon.com/Cork-Roll-3MM-Bulk/dp/B00ZNDJA8M/ref=sr_1_12?keywords=cork+roll&qid=1636295620&sr=8-12
Twinwall
https://www.amazon.com/Pack-Black-Corrugated-Plastic-Board/dp/B07HXBTSWG/ref=sr_1_6?crid=14AYEWL005Y67&keywords=black+coroplast+sheets+48x96&qid=1647008931&sprefix=black+coroplast+sheets+48x96%2Caps%2C202&sr=8-6