Hey Felix, glad you’re enjoying Openframe!
As of right now, the shaders that can be run on Openframe must be compatible with glslViewer, since that’s the utility that we’re using on the Pi to run the shaders. The easiest way is to write shaders using The Book of Shaders online editor, which let’s you save shaders directly to your Openframe collection, and push from there. (I should say, I’m not very knowledgable about shaders… the shader support that Openframe has currently is 100% thanks to Patricio, the author of The Book of Shaders and glslViewer.)
So right now, shaders from shadertoy won’t run without some porting (which at least one person has done successfully), though we’d love to support a wider variety of shader artwork in the future!