XClicker
Fast gui autoclicker for x11 linux desktops
...The user interface may look different depending on what gtk theme you are using. The highest I have got with it was around 750cps, but that was still with 1-millisecond interval. With 0 millisecond interval, the focused application may freeze. Safe mode, to protect from unwanted behavior. Autoclick with a specified amount of time between each click. Choose mouse button [Left/Right/Middle].