Cliclick
“Cliclick” is short for "Command-Line Interface Click". It is a a tiny shell / Terminal application that will emulate mouse clicks or series of mouse clicks (including doubleclicks and control-clicks) at arbitrary screen coordinates.
Hence, it is a tool for automating / scripting things that cannot otherwise be scripted (for instance, using AppleScript). Other than GUI Scripting, it does not require "Access for assistive devices" to be activated in the System Preferences.
Note: If you don’t know what “Terminal” is or have never used a shell, please do not download cliclick.