[Mashiro]

Why exactly can't you let them run 24x7? The power usage is so small that you'd end up only paying a few dollars/euros or whatever currency per year for a Raspberry Pi... you pay more for running your computer for just several hours every day. Is noise a problem? Usually they make no noise unless you actually install a active cooling fan. To avoid this you can get some nice cases that are made fully out of head conductive material like aluminium. So the whole case is the cooling. I checked out benchmark videos and they do help quite a lot compared to those small heatsinks or such. One name I have for you "flirc". Is the light of the LEDs a issue? You can actually disable the PWD and ACT LED. See here.

Anyway. So using them as a server is no option for you. That kills already million possible ideas and things to do. Not doing emulation also kills of some great ideas (retro console, arcade stations and etc). Left overs are educational purposes such as learning to code, programming robots and similar things. Learning how to use Linux also works really well since you can easily reflash the OS when you mess it up. Other things you could do with it... maybe a media center? Kodi alpha for the RPi 4 finally has the ability to use the full power of the GPU and playback real 4K content. That opens many channels for media consumption that older RPis couldn't provide due to lack of computing power.


I have three RPis left unused (original RPi 1 B, RPi 1 B+ and a RPi 3 B+), too. Just really not doing anything with them. I put them away. The RPi 3 B+ I have in a NES case with active cooling, controllers and a 64 GB µSD from Samsung full of NES, SNES and N64 games running Retro Pi. However no time to play...


For many more ideas I actually recommend to check the official RPi forum. They have a forum for projects. People post their ideas there to introduce their projects, show them off or simply get help. That can get you ideas .