Leg levelers for IKEA Lack table or anything with a 50mm square leg. I printed them at .30 layer height with petg and they work fine. They provide a maximum adjustment of 10-11 mm per leg.
I have also included a wrench to help with the adjustment if you need it. I was able to do it with my fingers just fine but if I had a wrench that size I would have used it for sure.
Update 3-22-19: I did print the wrench and it works very well. It's admittedly a little loose fitting but still works great and isn't a waste of time and plastic to print. I am glad I have it now for when I move my Lack enclosure. It makes adjustment way easier.
Check out these other things for IKEA Lack table...
Stacking leg couplers: https://www.thingiverse.com/thing:3488697
Leg stiffeners: https://www.thingiverse.com/thing:3490946
Adjust the infill and resolution to your taste. I can't remember what infill percentage I actually used when I made them so I guessed at 20%. The wrench was printed with 20% cubic infill + 3 perimeters and was plenty stiff.