These T-nuts are perfect for mounting practically anything to a Skadis pegboard.
Kudos to @6d6178 for the original design.
I love the simplicity of designing Skadis holders with these nuts because you just need holes in the model for the screws. That's it!
Check out his collection of T-nuts-related models or my models to find awesome designs or get inspiration.
For a deep dive into designing parts check out the original models description.

My remix has no need for nuts or any tapping/drilling.
You can directly screw M3 screws into the T-nuts when mounting stuff.

I recommend printing them lying flat on the bed, so the most strength is in the direction the nuts are pressed against when mounting stuff to the Skadis.
The model should already be correctly oriented.