Flashlight - Control your Mac with a keystroke.
Transparent Screen Lock - Password protect your workstation or server with "Transparent Screen Lock" while monitoring programs that are running.
Tiny Flashlight + LED - Tiny Flashlight + LED is free to use application that can be used anywhere else, having nicely built-in functionality.
ClearLock - A transparent screen locker.
Torchie - Touch to Torch
BlueLife KeyFreeze - FREE Windows application that blocks your keyboard and mouse without “locking” the screen.