I feel like the already awesome and huge roster of vehicles made for Blockland could use an addition of a bit more off-road styled, bulkier vehicles. Here's a few suggestions:
Baja TruckA simple baja truck. The most nimble of the three with good handling, decent suspension and speed.
Rally TruckA slow and bulky truck. Slow acceleration, can tip over, if you try to steer too hard.
Mud PluggerA rather bouncy car, much like the freestyle buggy. Great on rough terrain, but not exactly a track car due to it's low speed.