Let's start with Voltron. Very popular cartoon, but never made it to any systems.

Thundercats was another, but I think it came out for computers at least.

While there are many Transformers games now, the mid-to-late 80's severely lacked a TF game. One was released on the Famicom, but was so bad it didn't make it to the US.

Discuss this and/or add your own...