I wanted to make a list of power supplies that can work with the Stomp, most of these come from online and YouTube by seeing other guitarists
(And bassists!) and how they power them. Even though they seem to work with Stomp, Line 6 has Clearly said in their HX Stomp FAQ that they advise to use the provided power supply. To make these power supplies work, you'll need some extra accessories.
You'll need a current doubler, (NOT A VOLTAGE DOUBLER!)
and a centre negative 2.5mm adapter (Center for you yanks!). The HX Stomp has a power draw of about 800-900 mA, most power supplies will have 9v 500 mA or higher, these are the outputs you are looking for on a power supply. Power Supplies like the Cioks dc7 will have 9v 660 mA, this will not hurt the stomp. So here are the Power Supplies that should work.
Voodoo Lab Pedal Power X4 Isolated Power Supply https://www.long-mcquade.com/114125/Guitars/Cables---Power-Supplies/Voodoo-Lab/Pedal-Power-X4-with-Adapter.htm
Voodoo Lab Pedal Power X8 Compact Isolated Pedal Board Power Supply https://www.long-mcquade.com/172388/Guitars/Cables---Power-Supplies/Voodoo-Lab/Pedal-Power-X8-Compact-Isolated-Pedal-Board-Power-Supply.htm
Voodoo Lab High Current Power Supply https://www.long-mcquade.com/70394/Guitars/Cables---Power-Supplies/Voodoo-Lab/High-Current-Power-Supply.htm
Strymon Ojai High Current DC Power Supply https://www.long-mcquade.com/73948/Guitars/Cables---Power-Supplies/Strymon/Ojai-High-Current-DC-Power-Supply.htm
Strymon Zuma Power Supply https://www.long-mcquade.com/78116/Guitars/Cables---Power-Supplies/Strymon/Zuma-Power-Supply.htm
Truetone CS12 Pure Isolated Power Brick https://www.long-mcquade.com/61870/Guitars/Cables---Power-Supplies/Truetone/CS12-Pure-Isolated-Power-Brick.htm
Truetone CS6 Pure Isolated Low-Profile Power Supply https://www.long-mcquade.com/95105/Guitars/Cables---Power-Supplies/Truetone/CS6-Pure-Isolated-Low-Profile-Power-Supply.htm
Cioks DC7 https://cioks.com/products/dc7/
For the Cables
Strymon Power Supply and Line 6 Pedal Current Doubler Cable
https://www.logsdonaudio.com/cables/strymon-power-supply-and-line-6-pedal-current-doubler-cable
Voodoo Lab Current Doubler Adapter https://www.long-mcquade.com/15778/Guitars/Cables_Power_Supplies/Voodoo_Lab/Current_Doubler_Adapter.htm
2.1mm to 2.5mm DC Crossover Cable https://missionengineering.com/shop-2/products/cables/9v-2-5mm-dc-crossover-cable/
*If your wondering why everything is so expensive, It's in CAD*
@Digital_Igloo I hope what I've said is correct! If not please let me know!