UGREEN (99% positive feedback lifetime) via Amazon offers its 10000mAh GoPro Battery Pack Portable Charger for $22.39 Prime shipped when code B32BN2JU is used at checkout. Normally $28, this brand-new product is seeing its first tracked discount. Though ratings are light here, UGREEN stuff is generally well-rated.
Nomad Base Station
UGREEN GoPro Battery Pack Portable Charger features:
Dual Charging Channels — USB Port and Gopro Battery Charging Slot, the 10,000 mAh power bank for Gopro Hero enable you to charge the backup battery and your Hero 5 / Hero 6 or other smartphones at the same time. A 100% charge equals GoPro Hero 5/6 battery 5 times, iPhone 8 4 times, iPhone X / iPhone 8 Plus / Samsung Galaxy S8 Note 8 / Nintendo Switch twice at least.