My Flexispot standing desk didn't raise to quite the right height for me (I'm 6ft 6) and so I designed and printed these feet to raise the desk a few more cm and to stop it sinking into the carpet quite as much. 

I have designed them so that you can still access the desk's built in adjustable feet.

I printed with 5 walls and 25% triangular infill which appears to be stronger than is strictly required.