The Wee Blinky kit from the Maker Shed is an easy-to-solder two (2) LED blinker circuit. It comes with a 9V battery snap, but will work with almost any voltage from 3V to 12V. A 9V battery is required but not included. It’s tiny, it blinks, and it’s a great kit to hone your soldering skills since it’s cheap too!
In the Maker Shed: Wee Blinky kit