Is there a keyboard automation program for the Mac?

I used Keyboard Express (Insight Software) for my PC. It is for keyboard automation, i.e., uses shorthand for shortening keyboard work. Insight Software does not make a similar program for the Mac.

Does anyone know of a similar program for the iMac?

I'm not really sure I understand what the program does, but are you looking for something like this?

Automator Virtual Input V3.0 Take control of the keyboard and mouse via Automator

I think the OP is referring to something more like Typinator or TextExpander.

(and there are many other similar programs, some specifically aimed at coders or other "niche" users)

I was thinking maybe the OP was looking for something like Startly - What is QuicKeys4 for Mac OS X?. it has the ability to execute sequences of keystrokes and mouse clicks.