Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:3317368.

Printed from TPU this strap is designed to hold a power brick (e.g. aquarium lighting power supply) of multiple different sizes using one or two screws and a zip tie. Print using lower infill for maximum stretch-ability, the grippy nature of flexible filament holds them in place quite nicely with minimal time/material cost. Haven't tested this on many different size power bricks, so let me know if some modifications to the design are needed for your application.

Edit: Added a thinner and textured version