I saw a video of someone leveling a countertop with a laser and little markers placed on the top of the countertop. I couldn't find the original developer to buy a set so I made something similar. Wonderful concept. If you know the original concept developer please post it as a comment.

Note the STL requires you to have a multicolor capable printer and you will have to mark it at the levels you prefer. I used a Bambu X1c with AMS which worked great.