I got tired of my keys jingling and taking up so much room in my pocket, so I went looking for options. I first got a cheap key organizer on eBay. It was large, sharp, would come apart and was generally awful. Then I splurged and bought a KeySmart organizer (and extension pack) which is awesome. It sits in my pocket comfortably and quietly and keys can be flipped out with one hand (with practice).
To get my unusually long office key to fit on the standard size KeySmart, I matched it with an extra small filing cabinet key. (If I could buy it again, I would buy the extended (longer) version to fit my long office key.)
To get my office door access “puck” to fit, I matched it with the key ring piece.
And added the thick key ring that I bought off eBay for another project.
The spacers come with the kit and are optional. I could squeeze in two or more keys into this set as long as I don’t mind the keys rubbing against each other. If spaced correctly, the keys should not have to be held too tightly against each other to keep the KeySmart secure but usable. I’ve even had to loosen the screws to get the tension just right (and the screws still hold their position thanks to o-rings).
Just recently, I added a Thinguma Tripod Tool for use with my camera plates. This only require removing 3 spacers.
Although it sticks out of the KeySmart, it is not a noticeable difference in my pocket.