I made felt covers with elastic, one green and one black, for a round card table. Snug fit. Smooth flat surface.
Dealing cards, poker chips, game pieces, boards, puzzles. Got to have a good flat smooth surface. We use our game table for all game activities.
At the most I could see embroidering something on my felt on outer edges, but that might even interfere with game pieces.
There are a lot of accessories for cards and games. I could see quilting those. Bags, boxes, covers, totes, wallets and pouches for game money, drink coasters, cover for poker chip carousel.
I made pretty little beaded draw string money bags for mahjong.