Picked up some neat hardware and want to start learning Full Stack development, advice?

Hey everyone, i just got all of this for $1,000 and plan on flipping most of it, but I want to keep some for home lab tinkering. The servers and UPSs are still in their original boxes I believe.

I’ve been wanting to become a full-stack developer for a little while as it seems like an area I would enjoy as a career path. But now with all of this shiney hardware, I’m feeling some FOMO in just what I should keep for using as a learning tool. I don’t want to let go of something that might be useful in my journey!

So my question is, is there any particular combination of things you’d suggest I keep so that I can maximize my opportunity to learn? I thought you all might have the experience to be able to say that X, Y, or Z will come in handy while exploring different avenues because you may have used something similar/wished you had something similar at one at some point.