Basically just the CPU fan, case, and PSU (if you're lucky). If someone can figure out how to get Doom running on just those 3 things, young people will be able to ascend.
I feel like the military intelligence industry community conspired to introduce RGB components so that windowed PC cases would become industry standard, thus making it easier for them to power up any PC that is connected to a power source via BIOS bypassing line of sight technology.