Here’s another one of those, “Why didn’t I think of this before?”
You can easily fix a wobbling table with sliced wine corks, which are perfect since they can really grab some friction while re-using them will be environmentally friendly too.
Tired of spilling coffee on your homework papers or laptop keyboard? Don’t waste perfectly good napkins to stop the wobble. Stick a few of these cork discs in your backpack or pocket and use them to steady that shaky table.