@gpowerf It's not exclusive. Once I had an amber on black screen with a Hercules card on an IBM XT Clone! :)
@M0KHR I just tagged Hercules because it's the only mono graphics controller I remembered :) In fact, I also used an XT clone with an amber screen and a Hercules card.
@M0KHR at home the first IBM clone my parents bought (8086 with an 8086 math coprocessor) had a green on black screen :)
@gpowerf We had plenty of 3270 terminals in green in the uni labs, but by then cheap VGA monochrome and colour screens were coming onboard quite fast.