CSS-DOS — A computer made of CSS
An entire PC built in CSS.
LisaOS Emulator
A Lisa. In the browser. While I never used a Lisa, and while I've never even seen one in person, it's still wild to me that a computer from my younger days can now just be emulated in a browser.
Andrew Warkentin
A honking great collection of reto operating systems to play with.
tokenspeed — feel LLM tokens-per-second
Emulator to get a feel what N tokens/sec really feels like.
PDP 11/34 Emulator
I never used one, but I'm pretty sure I've been in the same room as one (having once worked for a DEC dealership who installed and maintained various PDP machines).
JVic - The web-based VIC 20 emulator built with libGDX
The second computer I owned, on the web, in your browser.