I am not sure if this is in the correct forum but here goes.
This belongs in mining.
I mentioned that I had many dozens of relatively idle CPUs which could be doing other work.
I was told that CPU based coins are not worth the time/effort at this point so I wanted to ask a similar question based on another resource.
That is correct, you can't do anything with your CPUs.
This 3KW of power, I look at as a resource so my question is, what kind of hardware might be worth building or buying in order to general coins which might have some value.
Do some searches on mining hardware. Checkout some ASICs like bitmain's S series.