Legos. I have 30 blocks. I have levelers but always put as many as I can under the levelers before leveling the rig. I do this to reduce the workload of the leveling mechanism as much as possible. Sometimes I'll also put blocks under the wheels if the site if too far off.
2015 Greyhawk 29MV
Honda CRV toad with Blue Ox baseplate
Ready Brute Elite towbar with braking system
TST 507 Flowthru TPMS