Hi, I have had the same issue before.
About 15 years ago, when I started the bachelor degree in architecture I wanted to learn rhino to create something like an eye catching design. I knew Rhino is the best tool to design it (and Microstation and FormZ but Rhino is the most userfriendly). I installed Rhino. I spent 10 minutes and I was just thinking. Okay. I it is cool but what’s the point of this hundreds of icon?
I turn back and I just started using Moi. Now, it is about 2 years when I started using, considering Rhino as a design tool again. What changed my mind? I started thinking again. I started evaluating again. The biggest issue was the UI. After spent some weeks and do more research of the usage of the UI I started building my custom Icon sets. Just what I needed. I removed all unnecessary icons just to keep it simple.
All in all. I recommend to provide predefined icon sets by professions separately by selecting the most common command icons used by the given profession or tasks to avoid the hundreds of icons that confuse.