In the course of carting my Corsair K70-RGB around, a couple of the rubber feet on the bottom of the keyboard came off, one of which I lost. After searching Corsair's webstore in vain, I contacted Corsair about buying replacements. They don't sell the rubber feet, but they were willing to RMA my keyboard because it was wobbly. Unfortunately, I would have recieved a newer model with an updated controller. That's usually a bonus, but I'm using the Open Source ckb to drive the keyboard, and support for the newer model is still in a development branch.
So I went looking for an alternative solution.
I carved a replacement rubber foot out of some old tire rubber. While that worked, there's a better solution.
Corsair does not sell replacement rubber feet for the K70, but they do sell replacement wrist rests. Those wrist rests sport three of these same rubber feet on the bottom.
They appear to be the same as on the K95 and its wrist rest. I used Gorilla brand superglue gel to affix them to the keyboard, which bonds them more securely than Corsair's original adhesive.
So for $10+s/h, you can buy a set of three rubber feet... they just come packaged on a wrist rest.