Amiga Workbench could be used mouseless by using key combinations to move the mouse around. It was cumbersome, but just good enough to let you use the system if your mouse was broken, or you had plugged a second joystick into the mouse port and couldn't be bothered swapping them to launch a game. Later there were add-ons like Reqtools and MCP which let you use keys more, e.g. Escape to close a window, or Return (Enter) to hit OK on a dialog box.