Make your own scratch boards for your cat! This is designed to work with this cardboard strip cutter: https://makerworld.com/en/models/669599-cat-scratch-maker-box-cutter-now-in-more-sizes#profileId-597254

Available for 3 different size:
480 x 480 mm, print four Quaters and use super glue
400 x 480 mm, print two Quater1s and two Quater2s, and use super glue
210 x 360 mm, print two Halfs and use super glue

Edit: wrong file for 480x480 was uploaded and now corrected. The privious file was actually 400x480