There’s a lot of examples, you should go to an electronics store and look for some examples. As far as description, there is no specific description. What you’re describing is some form of indicator or feedback mechanism. It tells the user some type of information.
Off my head, Jawbone does a great job of non-display based UX.
The Jambox and other Bluetooth speakers do a great job of communicating purely via voice prompts.
The UP fitness tracker communicates via LED’s and haptic vibrations within the material.
Fuel Band used an LED matrix for display instead of a screen.
Canary has a glowing ring to indicate it’s activity
Lots of examples out there though for different uses of LED behavior, etc.