You can pick up an external battery (or "power bank" if you like) on Amazon for a pittance, but most of those have slow charging ports and mediocre capacity. With USB Type-C, you can finally get batteries that charge laptops, phones, tablets, and more all in one. However, these devices are more expensive, and it can be difficult to untangle all the charging standards. The AlsterPlus USB-C battery on Kickstarter has everything you could possibly want from a power bank, but it's on the spendy side.
You'll get the best charging compatibility from a battery with support for USB Power Delivery (USB-PD), and the AlsterPlus has that. It's actually USB-PD 3.0, which is still very rare. Using a reversible USB Type-C plug, a 3.0 device can output as much as 100W over a single port. That's as close to future-proof as you'll get in high-power charging right now. Current high-end laptops like the 15-inch MacBook Pro and Pixelbook charge slower than that over Type-C—the Pixelbook is 45W and the MacBook can handle 87W.
The AlsterPlus doesn't just have a single port, though. It has two that support 100W output, along with two more USB-A ports with 18W Quick Charge 3.0. All told, the battery has a maximum simultaneous output of 156W. That's the highest of any battery I've seen and would allow you to charge multiple laptops, tablets, and phones at high-speed.
With all that super-fast charging, you're probably wondering how long this battery is going to last. Well, probably longer than you think. The AlsterPlus has a capacity of 27,000mAh, which is enough to completely charge a 15-inch MacBook Pro about four times. It's enough to juice up most Android smartphones seven or eight times. You wouldn't want it to be any larger because it's right at the 100Wh limit for TSA carry-ons in the US. Any more, and you couldn't fly with it. The AlsterPlus also comes with a 100W wall charger that can refill it in just an hour.
In addition to all that quick charging, the AlsterPlus can also function as a USB hub. In these days of laptops with just a handful of USB-C ports, you might need that as much as a battery. The AlsterPlus has one USB-C that acts as the data-in, allowing you to connect another Type-C and two USB-A devices to the battery for data connectivity. This is independent of charging, too.
The AlsterPlus Kickstarter runs through early January, and it's already far past the funding goal. If you want to secure a unit, it'll cost you about $160. That's cheaper than a lot of batteries that don't offer nearly as much power or capacity. The designers say batteries will begin shipping in February.