Our BMW had an insert where you could put the car key and something else (in our case, garage opener) that fit into the cup holder. I got so much use out of it, that when we bought our new Ateca I wanted to have the same again. 

Designed for the smaller of the two cup holders for the KH7 Seat/Cupra Ateca. It fits the key fob and we use the other slot for our garage opener. 

I've printed in PLA but I live in Germany so temperature is not such a huge concern just yet, I'm sure in warmer countries you'd want to consider a more temperature-tolerant material.