I bought a couple of different rivet threaded nut insert tools from Amazon. The smaller one is here: https://amzn.to/2l85Jbg It comes with 8 different mandrels (Metric M3, M4, M5, M6; standard SAE 1/4-20, 10-24, 8-32, 6-32).
The larger tool is here: https://amzn.to/2lcKvJf It comes with 7 mandrels (Metric M10, M8, M6, M5; SAE 10-24, 1/4-20, 5/16-18)
My design is loosely based on the one here: https://www.thingiverse.com/thing:2930968
I didn't use any of the dimensions or files, so this isn't a remix, but hats off to the original design! That design wouldn't work for me since it was intended for 6 mandrels. Both of my tools have more than that. I also didn't want to have to carry the entire set since each of my projects typically only requires one size. Just grab the tray I need and go.
I will make a tool box that all these will fit in, along with the smaller tool, and the wrench. I'll upload the file probably later this week.
These were designed in Fusion 360. I've uploaded the design files, feel free to modify as you desire.