Xcentz 18W USB-C PD 10,000mAh Battery Pack | $15 | Amazon | Use the promo code 546ZMYUH
If you want a portable, future-proof battery pack, consider this Xcentz 18W USB-C PD 10,000mAh unit. To be clear, this is designed for smaller devices, like smartphones (charges an iPhone at the maximum possible speed) but it should work on iPads and the Nintendo Switch as well. Better still, you get a USB-C to USB-C and a USB-C to USB-A cable in the box, which is amazing.
Make sure to use the promo code 546ZMYUH to get the $15 price.