I think that more people kept the boxes to their Intellivision games than for any other system. There was a really good reason for this, too! The intellivision games came in these really neat flip top cover boxes! They also had these plastic tray inserts which the carts sat in, so you could reuse the boxes over and over again to store your games! Atari, Coleco and other games opened at the top, and there was really no good way to take the cart and put it back in the box without some form of effort. So, you guessed it, most Atari and Coleco boxes (and other systems too) got tossed. Not Intellivision though.
You may actually have some intellivision boxes that are cheap like the Atari ones. These are the later (1983 or later) releases when Mattel started getting cheap and stopped giving a damn. They even stopped the plastic cart trays. Man. Sad.
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