If you're on the market for a convenient pocketable power bank, Anker's PowerCore Slim 10000 PD is worth considering. It features a compact design that easily slides in your pocket and can charge two devices simultaneously. It's currently down to $32 on Amazon, which is 20% off its regular price.
The battery pack has two ports, a traditional 12W USB-A outlet, combined with a USB-C PD port that can deliver up to 18W to quickly charge two phones at once. You can also fill up low-power devices like earphones thanks to the product's trickle-charging mode. For added convenience, the USB-C connector is used to charge the power bank, which can be filled up in three and a half hours if you're using a compatible PD wall charger.
The PowerCore ships with a USB-C to USB-C cable and travel pouch for extra practicality, and comes with an 18-month warranty. It has received positive reviews on Amazon, with an average rating of four stars.