I used the yellow lego blocks with the B190. I think I had two sets - one pack of 8 and one pack of 4, and there were a few times that I needed all of them (certain campsites with an annoying slope...sigh). We bought new orange blocks for the trailer, so I threw the yellow blocks in as part of the deal when we sold the B190.
No particular reason for switching brands (I think we went with the orange because we wanted new ones for the trailer, and that's what Camping World carried), although the orange blocks do have the option of an integrated wheel chock, which you probably don't care about (I often chocked my B190, but that's because I grew up in trailers - it didn't need a chock at all). Both brands worked just fine, though the orange ones are better about not catching small stones and such for when it's time to restack them. We did snap a yellow block in half one time (our fault, not a failure; I was trying to be clever), but even then we could still use it for some purposes just fine - in the middle of a stack, it doesn't matter that it's broken in half.
Wooden blocks would work, too, but you have to make them and seal them. Plus you have to store them somewhere - the plastic blocks come with a nice bag to store them in, which is nice if they're going to live inside the camper when not in use.
I saw a motorhome (Class C IIRC) a couple months ago without any leveling capability apparently. They scavenged a fair sized stone to drive up on. It looked unstable and cheap, and was probably hard on the belts in that tire. Don't take that route...do something better than that.
1995 Airstream Classic 30' Excella 1000
2014 Ram 2500 Crew Cab with Cummins 6.7L Diesel
Sold but not forgotten: 1991 Airstream B190
Sold: 2006 F-250 6.0L Powerstroke Supercab