A Mister does a good job of recreating period appropriate load times and quirks. You can put it in whatever old computer case you're most nostalgic for, connect an old CRT monitor and most peripherals should have some USB converter if necessary.
The last version of TempleOS is included, but I installed it myself, and I didn't bother to include most of the images that I just installed by myself in the credits.
I'm also planning to add earlier versions as well as the later forks at some point.