Noticed Anker has a 20000mAh power bank on sale.

This one has both usb-c and micro usb inputs.

Amazon product: Anker PowerCore Essential 20000 Power Bank, 20000mAh Portable Charger with PowerIQ Technology and USB-C Input, High-Capacity External Battery Compatible with iPhone, Samsung, iPad, and More
Customer Reviews:
This charged my phone to 77% (Google pixel 2 XL) and my friend’s phone to about 40% (iPhone 8) and it still had four lights on (which means it was still above 75% power). I never go anywhere without it. | just a tip; if you have devices with different types of chargers I recommend getting a multi cord instead of carrying around 3 cables I have a Google pixel 2 XL which uses a USB C, Airpods which use a lightning adapter, and my Bluetooth speaker which uses a micro USB and having one cable that can charge all three is super convenient I can just throw the battery pack and one charger in my pocket and not have to worry | *EDIT* I just thought I would update this, I bought this back in the beginning of January and it’s now the beginning of September, this thing has been dropped and abused and beaten up and it’s still working just like the day I bought it.