I have done some research to use for EDC, backpacking, and with portable solar power for power outages.

I have both Anker and RAVPower power banks. I also have USB chargers and micro USB cables from both. I would recommend either company and they both run discounts on Amazon from time to time.)
(Usual disclaimer, happy customer, no financial interest.)

The key to buying a power bank is deciding what you plan to use it for. For backpacking a 10-12k mAh capacity will charge the items you mentioned for a couple of days without being too heavy.

For others who may be looking:
A 5-6k mAh power bank weighs very little and is good for when you're unable to get to an outlet for a day. I EDC one and it gets used often.
A 26.8k mAh power bank is the standard biggest size that's FAA approved and is a good car camping or home power outage choice. It will weight you down on foot.

There are many different models so it's important to look at the inputs/outputs, and charging technology.

I would recommend a unit with both micro USB and USB C inputs/outputs as they will give you more options.

A fast charge input and output are important. Most cell phones have fast charge capabilities so it is a good feature to have.
The unit itself should charge quickly since the larger it is the longer it takes to charge.

One important thing is to use it like a spare gas can. You wouldn't overfill your gas tank and lose backup gas. Don't charge items past 90% so you can keep more power for later.

RAVPower has a good blog to learn about power banks, http://blog.ravpower.com