Not sure if this is what you’re talking about as they’re not particularly cute, but at least in the US they’re probably more commonly called holsters.

https://www.amazon.com/Scopester-Stethoscope-Holster/dp/B01ATUOTX4

I've had this for years, and I really like it. I was skeptical about the quality, but honestly aside from the stethoscope falling out maybe once every couple shifts I have no complaints. It clips right onto the waist band and doesn't pull pants down one bit... at least not the scrub bottoms I have that tie in the front.
https://www.amazon.com/Scopester-Stethoscope-Holster/dp/B01ATUOTX4