Adafruit On-Off Power Button / Pushbutton Toggle Switch [ADA1683]
Push once to turn on, push again to turn off! This clicky switch makes a great power switch or mode toggler. We like this switch because it's breadboard friendly and more fun than a power switch. Can reliably handle up to 500mA and up to 50V. This is a really satisfying switch.
The leads are not on a perfect 0.1" grid so for use with a breadboard just bend the leads out just a tad and snap into a solderless breadboard or perfboard.