I made this nice looking case for 30 000 mAh Aukey powerbank. It should also fit another powerbanks, but you'll need to customize it. I included Fusion 360 .f3d file for customizations.

Print settings:

• It is important to print it on the either longer sides (the wall where is the text “Designed by HelloItsMeAdm” and the opposite wall) or on the back and front sides (inputs and the opposite wall). If you would print it on the honeycomb sides you wouldn't be able to print bridge above the powerbank.
• By printing it on the sides it's recommended to print it with a brim (or even raft), so that it doesn't fall during the powerbank insert pause by accident.
• I also recommend printing the long side horizontally with the Y axis (shown on the picture below), so that when doing fast moves it doesn't fall because of the weight.
• If you print on 0.2mm layer height make sure to add pause command on layer 438 - 87.60mm height so that you can insert the powerbank.
• Supports are not needed.
• All those settings should be in the examplepowerbankcase.3mf file.