Gravity: I2C 3.7V Li Battery Fuel Gauge | DFRobot DFR0563 | Core Electronics Australia
Amazon.com: Battery Pack, UPS Power Board, Easy Installation Durable UPS Power Board Dual Color Indicator Charger Portbale for Raspberry Pi Zero : Electronics
Raspberry Pi Zero Lipo Fuel Gauge With Safe Shutdown | thinkering
Adafruit MAX17048 LiPoly / LiIon Fuel Gauge and Battery Monitor [STEMMA JST PH & QT / Qwiic] : ID 5580 : $5.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Adafruit LC709203F LiPoly / LiIon Fuel Gauge and Battery Monitor [STEMMA JST PH & QT / Qwiic] : ID 4712 : $6.95 : Adafruit Industries, Unique & fun DIY electronics and kits