I also like Shadron, it has quite a bit more capability (being able to use your own textures is pretty important! I can actually get work done with Shadron, can't do that reasonably with shadertoy). The downsides are the small community size and no automatic sharing / GitHub / OSS integration.
Other features include UI sliders, image saving, pretty decent library, unlimited flexible layers, way easier debugging, and lots more. I'm a huge fan, I'd love for more people to use it too.
Other features include UI sliders, image saving, pretty decent library, unlimited flexible layers, way easier debugging, and lots more. I'm a huge fan, I'd love for more people to use it too.