Here is a tool holder inspired by the "Ender 3 Tool Holder" by Macromoon, using some aspects of that design and also parts of the "Ender 3 tool holder with card reader and scraper" by lifififi. I also used the rails from "SD Card Extender holder for Creality Ender 3" by Kenji815 to fit it to the printer.

Why did I design this?

Well, I liked the shape of Macromoon's design, however it didn't contain all the tools I would have liked to store. Additionally, tools hang from the front of his, which could get caught in the moving parts of the printer for tall prints. The issue with lifififi's design is that it relies on gravity to stay on, whereas I would prefer a more secure fit to the printer.

Hopefully somebody finds this useful!

Edit 1:
I've included some photos of the print of version 1. There were a few issues: without support, the rails do not print very well, and as I would rather not use support printing this piece, think I will split the design into two snap-together parts. The other issue is that with all the allen keys in, there is no room for the spatula.

Edit 2:
Uploaded the new files (v2). Will get rid of the old one after the new one has been printed and checked. I've uploaded it in various ways to make it easier for anyone to remix the design.

Edit 3:
Included photos of v2. The tools are all a bit too close, apart from the snips, alan keys and USB adapter. They do all fit in, but only if placed in a certain order, which also makes it harder to take a specific tool out for use. Will address these issues with v3. If you add supports only under the rails (already in the gcode if you want to print straight from that, or in the cura project file) it prints perfectly fine.

Edit 4: The final version, v3, has been uploaded. All other versions will be removed, as will the photos of them to avoid confusion. Some minor issues with the stl file means that the letter d may have a chunk cut from it, and the fit between the SD card, screwdriver and spanner is extremely close but I'm happy with the final product.