Amazon.com: SDTC Tech 8-Pack 3.7V 18650 Battery Holder with Soldering Pins 1/2/3/4 Slot Black Plastic Battery Case Kit for DIY Parallel or Series Circuit PCB Projects(2 Per Size) : Electronics
12v 3s Power Wall 18650 Battery | 18650 Battery Holder Power Wall - 12v 3s Power - Aliexpress
1022 - Keystone - Battery Holder, AAA x 2, PCB
12mm Coin Cell Breakout Board : ID 1868 : $1.95 : Adafruit Industries, Unique & fun DIY electronics and kits