I have one bag of the lego blocks, but mostly only them as a small stack under the tongue jack.
For leveling, I made a small variety of 2x6's in various lengths and mostly use them under the tires.
One other thing about my camper is that if it is exactly level when first parked, then it will be very slightly low on the streetside after the slide room is extended. What I found is that 3/4" is what it is, so I cut a couple of small pieces of 3/4" plywood, and drive the trailer onto those. Extend slide and the trailer is again perfectly level.
The small piece of 2x4 is screwed/glued onto the 2x6, and will keep the next layer of board from sliding/getting pushed back off as I drive up onto it.
Plywood pieces are short enough that one will fit on ground between the tandem tires while positioning them. I started out with just 3/4" dimension lumber for that, but found they broke easily. Plywood has held up without breaking.
I'm one who likes my trailer level, even if it's just for one night. And like one of the posters above, I too tend to stay in developed campgrounds, and have found they are mostly pretty close to level. I spent several decades doing bare minimal camping why traveling by motorcycle. I'm mostly done with the backwoods boondocking.
I want all the hookups these days.
EDIT: for what it's worth I also carry a small variety of small scraps of 2x6 and 2x8 to give to neighboring campers that need them. It's surprising how many times I've had folks camped nearby that forgot to bring a block to put under their tongue jack, etc, so it's good to be able to help out.
