I'm happy to know that!
Be sure to investigate custom toolbars and menus.
https://github.com/LibreCAD/LibreCAD/wiki/WidgetsSomething to note is that custom menus connected with Ctrl+Right-Click or Shift+Right-Click,
will not cancel the current operation, which could be useful for snap modes.
Also make sure to consider 'Keycode mode' in the command line's menu
(if you are using 2.2.0-alpha), which automatically accepts 2 character commands.