Hi cbassett82,
Welcome to Microsoft Community.
I'm Hahn and I'm here to help you with your concern.
For charging your Surface Pro 8 via USB-C while traveling, it's important to choose a power bank that meets the device's power requirements and is also compliant with airline regulations. The Surface Pro 8 charges best via its USB-C ports, and a power bank with a 60W Power Delivery (PD) output or higher is recommended for effective charging. Surface power supplies and charging requirements - Microsoft Support
The Anker 737 power bank you mentioned, with a 26k mAh capacity and rated for 87W, seems like a solid choice as it exceeds the minimum power delivery needed for your Surface Pro 8. It's also under the 100 Whr limit for airline travel, which makes it suitable for your needs.
Unfortunately, as a Microsoft agent I cannot recommend third-party power banks for you. But I would keep this question open so that other users or volunteers in the community can provide you with suggestions.
Remember to check the physical size, weight, and additional features like the number of ports or included cables that might be important for your travel convenience. Always ensure that the power bank you choose is within the airline's allowed capacity for carry-on luggage. Happy travels!
Your Sincerely
Hahn. W - MSFT | Microsoft Community Support Specialist