ShaderSketches
This is a repository that stores GLSL shader sketches I created while commuting every day. You can see GIFs of these sketches from my Tumblr.
I'm using KodeLife shader editor and GPD Win handheld PC for sketching. In my opinion, this is the best combination of portable development. I created all these sketches while standing in a train.
Note that the coding convention of KodeLife is a bit different from ShaderToy or GLSL Sandbox. You have to modify the code to run them on these environments.