I worked on a multiplayer version of the puzzle card game Set recently with a friend. It uses socket.io to communicate and Svelte for the front end. It’s a lot of fun to play with friends or alone: https://isaset.com/
I was going to comment that it doesn’t work well on mobile, but it looks like that’s on their todo list: https://github.com/ekzhang/setwithfriends I wasn’t aware of this implementation, thank you for sharing!