I feel like promoting a really cool project:

https://pcbox-emu.xyz

Cycle-accurate IBM PC emulation, covering hardware from 1980s up to Pentium 3 era; the author @qeeg forked 86box because 86box didn't want Pentium 3 emulation. It emulates real mainboards.

You can run old Linux distros or classic DOS games and such, faithful to original hardware. Coreboot supports (and boots) on some of the emulated boards.

I host her DNS! The website was re-done (not hosted by me) plus docs added recently.