I've been playing around a lot with WebSerial lately and decided to scratch a bit of a personal itch and make a better Serial Plotter. It's very much a work in progress but is working well enough for people to play with it.
You can try it out here: https://web-serial-plotter.atomic14.com/
It is a mixture of AI assistant and manual coding - which has worked surprisingly well. I find it particularly helpful for the UI and testing side of things.