unclutter
A tiny X11 utility that hides the mouse pointer once it has sat still for a while, so it stops parking itself in the middle of what you are reading.
Mark M. Martin posted unclutter in the early 1990s, and the idea has needed no improvement since: leave the mouse alone for a few seconds (-idle 5) and the pointer vanishes; touch it and it comes back. It became a fixture in the .xinitrc of people who live in terminals, and an obvious choice for kiosks, signage and media boxes that have no mouse at all.
The core protocol has no call to hide the pointer, so the original had to cheat with invisible cursors and windows — tricks that programs with their own grabs occasionally noticed. Once XFIXES gained a proper HideCursor, it was rewritten as unclutter-xfixes, which does the same job honestly. Under Wayland it is the compositor's business.