Let your action figures have some fun in their spare time. These pistol grip style RC transmitters would be perfectly suited to controlling cars or boats.
3D printed in resin, they ship on their printing supports, and will need careful removal. The resin can be brittle, so be careful getting them into your figures' hands.
For a 1:6 figure, 1:72 vehicles are the equivalent of 1:12. 1:64 diecasts, would be somewhere between 1:10 and 1:11. Hot Wheels and similar diecasts will be perfect as larger scale 'bashers'.
For 1:12 figures, 1:144 vehicles will be the equivalent of 1:12. Look at N gauge cars.
For 1:24 figures, 1:288 is the equivalent of 1:12. 6mm wargaming vehicles will work.