Wobble Wedges Rigid Plastic Shims, 30 Pack - Multi-Purpose Shim Wedges for Home Improvement, Work - Plastic Wedge, Table Shims, Toilet Shims, & Furniture Levelers - Black Leveler Wedges, Leveling Feet

I bought these to stabilise a washing machine, which sits on an uneven floor. Three of them stacked has worked perfectly - the washing machine no longer dances noisily across the floor. I'm very happy indeed. They're tiny and unobtrusive (which really isn't important re the washing machine, but might be if they're being used for, say, a dining room chair or a side table).

Can be used individually or stacked together as they won't slip. I've used them on cupboards and dining table and they work well

I discovered these while working in restaurants and got a pack for my house becasue they're truly the only thing that works when it comes to stabilizing a table or anything that wobbles. Nothing is more annoying than sitting at a table that shakes every time you touch it or set something down. Maybe it's an OCD thing but I can't stand it. My couch it a little off balance too. Whenever you sit on it you hear the other side hit the ground. These work perfectly to prop it up. They have the little grooves so you can stack multiple together and they wont slide which is perfect for the thicker gaps you're looking to fill ;)

These are perfect for that wobbly table. So much better than those bits of folded card!

I whent on their website and found out that this is a common solution for gym equipment/machines. They are much smaller than wedges commonly used in construction but the way they're designed they did their job. We have our machines sitting ontop of painted uneven cement so quite a few would wobble. We used to put black mocrofibers and they would work but looked tacky. I needed 2 max for some of the machines on one side. The design is amazing regarding them stacking and staying in place. Easy to use and I used about 6 total and used them on 4 machines. Took about 5minutes total. So far im super happy. As long as they dont slide out or anything we're good.