Build an 8-bit computer from scratch (2016)

I tried something similar when in college. Built a 8bit GPU on a breadboard, i don't remember all the details now, but it was such a fun project.[1]

[1] https://nabraj.com/blog/8-bit-gpu/

I did the whole thing, was able to get the Fibonacci numbers appear and learned a lot during the process. However, I would not recommend other people to try this today, because --

* It is not necessarily the best way to spend your time and money. You'll be looking at tens of hours on building it plus over $300 in parts, for a very slow and basic computer that you probably will forget and throw away at some point. Cutting and laying out wires are some of the most tedious and frustrating process. There are other cheaper, more efficient ways to learn how a computer works. It may or may not be worth the effort to you.

* The tutorial is really old, with some very questionable design choices and no updates from the author. Some of the designs are just plain wrong -- e.g. floating inputs or missing resistors. It is very unlikely you can reproduce it by strictly following the tutorial. You'll need to spend time debugging those issues and go to reddit to see other people's experience with this, potentially seeking help as well. No doubt debugging is an important part of designing and understanding the circuit. But only if you have the foundational knowledge and patience, of which I happened to have, but I can imagine that someone who does not understand digital electronics well enough can easily get lost and feel defeated.

* To make the previous point worse, some of the parts are hard to source, depending on where you are. (You'll likely fry or physically break a few components when building it.) Many of the parts are not very commonly used these days, and not exactly easy to acquire, if you only need 1 or 2 of them. I had to go to eBay to get some of them, which took about a week, during which I had to stop and wait for parts to arrive.

With all that said, this may still be the best resource out there that lets you build all these on a breadboard, as I am not aware of an alternative that addresses all the issues above.

Wasn't there someone who did a physical discrete logic implementation of the NAND to Tetris design?

I feel like that could be a good choice for someone doing this today because there's now a kind of a large ecosystem of resources for that design (not that it's inherently better somehow).

I also did the 6502 and added a Pi Pico for VGA output and USB input.

I'm still working on ways to add more to the design -- it's been a fun hobby. I actually enjoy cutting the wires and physically putting it together.

I kinda judge YouTube channel by the inverse of the speed I need to scale down/up.

Ben Eater is always among the top 10.