Some examples from mine setup:

• Shortcut to copy hex code of a color under a cursor
• Shortcut to enter text that would be automatically translated and typed in the text field without needing to copy paste anything
• Soundboard mode which binds keys on the keyboard for sound effects
• Piano mode, similar but for playable piano nodes
• Shortcut to display an image of broken screen (to prank people that seems to cannot control their hands)
• “Transport mode” for doing copy, copy, copy and then paste, paste, paste without switching windows back and forth

Maybe you have some ideas too?