The Pico-8 is great, but https://tic80.com/ is really cool too.
But it is not a clone of PICO-8. It offers a resolution that's very similar to that of the Game Boy Advance, so it serves as a nice transition stage towards GBA development. You can then enjoy your games on a console like Anbernic RG351P that's optimized for GBA games (2x integer scaling, same screen ratio). It's a specific use case, but one where TIC-80 shines.