White
A white screen is arguably one of the simplest and least arbitrary things a screen-driving information system can present, together with Black (to be released soon). Here are some implementations: https://white.paulfrischknecht.com/ (a PWA) https://play.google.com/store/apps/details?id=com.paulfrischknecht.white (a native Android app, listed in the Google Play App Store) https://www.shadertoy.com/view/msfGDM (a glsl shader, listed in Shadertoy) https://www.youtube.com/watch?v=QggJzZdIYPI (a YouTube video, not mine)