Sites and apps similar to Keyboard Checker include KeyboardTest. It's paid, but Aqua's KeyTest and Full Key Codes are free. Other options are Keyboard Codes Display and keyview. In total there are five sites and apps like Keyboard Checker for Windows and Mac.
PassMark KeyboardTest allows users to quickly check that all the keys on their computer keyboard are functioning correctly, check the keyboard LED's, look at the internal scan codes being generated by the keyboard and measure typing speed.
Australia
This great little utility was written by the same Korean keyboard god that also developed the LIMKB keyboard controller.
Full Key Codes is a little utility to display code informations about each key of the keyboard. The developers know why :-)
A little program to display the virtual key code and the key value (or the key name for non-character keys) for each key pressed.
