https://www.sparkfun.com/tactile-button-smd-6mm.html
Tactile Button - SMD (6mm) - SparkFun Electronics
SparkFun Electronics is an online retail store that sells the bits and pieces to make your electronics projects possible.
tactilebuttonsmd6mmsparkfun
https://www.adafruit.com/product/3983
Mini Soft Touch Push-button Switches (6mm square) x 10 pack : Adafruit Industries, Unique & fun DIY...
Put your project in stealth mode with these super slim, super tiny, and silent Mini Soft Touch Push-button Switches. They're less 'clicky' than tactile...