I've made a detachable Keychain, just add your own rings and keys. I've printed in PLA and PETG, the picture shows they are interchangeable, black being the PETG and Orange being the PLA. Tried to keep it small enough to not bother being in a pocket. Feel free to let me know if you'd like it a bit bigger.
It's printed with supports, I used a small pocket sized flat blade to remove supports. The hoops seem to hold up pretty well when leveraging the ring to assist in the twist lock.
The author marked this model as their own original creation.