I have known the Aukey brand for years. They offer inexpensive products that are still of decent quality. In addition to power banks and power supplies, there are at Amazon also bluetooth headphones, charging cables and other things that can be used for iPhone, iPad or Mac.
Aukey's PR department keeps supplying me with deals and special offers, which I like to pass on to my readers in the form of articles. If you install my iOS app and allow notifications, you will always receive the latest deals from Aukey on your iPhone.