The PLATO computer system was used for a some of the earliest video games in the 1970's.

https://en.m.wikipedia.org/wiki/PLATO_(computer_system)

PLATO IV seems the most innovative, with 512x512 pixels with a monochrome orange display. While it isn't quite a "console" is it okay to use these limitations for this game jam?

Now that I look at the official jam logo, showing orange text on an old computer, it seems like PLATO and other old computers should be covered. It would be nice to add this to the list on the jam page to make it official.

PLATO is 100% fair game. Any consoles/computers released around/before the listed consoles are also fair game.