There are many cool concept vehicle designs out there, but a LEGO Digital Designer (LDD) Builder, dunkleosteus_ldd has made an amazing concept vehicles with LEGO. The first one is some short kind of rover, named Spinner W-6. It’s just really unbelievable to see how wheels are made up! He is using 75937, 15712, 2654 for the wheel design, even they’re connected, but I’m not pretty sure that it will be strong enough to connect in real life. Not just that, there’s also many NPU (Nice Part Use) in this model!
The second one is some kind of drone, a space vehicle and it named 4Shell, you may know why is it named like that. It’s using the same technique as the wheels of Spinner W-6 (model above), but it’s for a turbine or propeller.