not-fu-kenworth-it

I built a small home server just as a learning experience, it's used as a file server and a minecraft server, what are some things I could do with the expansion slots since I really don't need a graphics card. I'm sure any cards aren't necessary, but I do like to learn about things by applying stuff

Super newbie here, I'm making a little home server for fun, 4 core cpu, 16gb ram, and probably 4tb hdds (4 1tb discs) I have 1 ubuntu desktop, 1 windows pc, 1 windows laptop and several chromebooks. I'll use Ubuntu server for my server, but for my Ubuntu descrop, how to I save and access stuff from the command line on my server? And what else do I need for the other stuff? I'll be saving a few cd roms on it, along with probably a minecraft game and possibly hosting a small minecraft server on my home server