On the topic of like repurposing various computer components. I used to see people using the circuit boards for like art projects or decorations. Maybe that's tacky.

Maybe having a bunch of DVD-R drives could be useful if you want to burn a bunch of DVDs at the same time. That's if these computers even have burner drives.

$WARNING there is 1 part of the computer that you don't want to take apart. PSU power supply unit. The PSU has high voltage capacitors inside of it, that can shock you and kill you, even if the computer is off. The PSU is a small box near the back of the case. It should be safe as long as you don't open that box. There's probably a warning sticker on that box.