Playmats are so fun to make!
It is a great time to go to the fabric store to try new types of fabric.
I go around and touch and feel all the fabrics and I purchase a small amount of each. I make a patchwork of all of the fabrics and my babies have loved it! Great textures include chenille, satin, even faux fur and textured faux leather. Back it with a fleece (add batting if you choose to), reinforce areas by tying the layers together with yarn (like tie-quiling), and bind with double bias tape!
Or, you can applique shapes onto each square, in different colors or fabrics so as your kiddo crawls to one square or the other they can experience something different.
Both my sons have loved it and have worn theirs out to pieces! LOL
HTH!