Alexa's Echo Buttons can trigger your smart home routines now - CNET
Amazon.com: Echo Buttons (2 buttons per pack) - A fun companion for your Echo : Arts, Crafts & Sewing
Amazon's Echo Buttons can now trigger Alexa Routines - Gearbrain
How to Stop Alexa From Listening
What Do the Echo Dot Buttons Do? - The Tech Edvocate
Echo dot 3rd gen not booting up tried holding the action button for 25 seconds nothing just stuck on the long spinning cyan ring (I'll put what happened in the comments) :
Caregiving and Alexa | What the Echo buttons mean.