Plug-and-Play/TV Games Platform
This one I never really considered until I came across multiple good examples, and they are a step above Tiger Electronics games.
Plug-and-Play TV Games, or Handheld TV Games were cheap, "toy-isle" games that hooked up directly to a TV to play one-off titles, coming with a cheap controller or even a light-gun.
I wouldn't look to add each and every one as a Platform, but a generic "Plug-and-Play" Platform like the legacy Mobile Platform could help give these a Platform to live on.
We looked into this and thought it was a good fit for sure. We might end up tackling this at the same time as better handling of similar platforms such as Tiger electronics.