I have gotten a simple reciever and trans attire to work (it has reverse polarity and can separately control two motors), I also have a simple gearbox that I attached to one of the motors. I was wondering what I could do with all of these components (I don’t really want to make an rc car becuase I have already made them before)
Ps. I do have a 3d printer so I think that could make it easier to do.
I always find it to work much better to first think "what do I want to build", then "how am I going to build it" and finally "what parts would I need for that". You try to start at the end of that process...
TORTLE_TECH:
and trans attire
Sounds interesting. But we are broad minded here. 
...R
How about an RC turtle?
All you need for that is a pot of food and you get a follow-me turtle. Works best when the turtle is hungry
How about a RC nerf gun? You could get one of those fully auto ones and use the gearbox to turn it and the other motor to pull the trigger (probably using a limit switch so it doesn't stall too much)