Here’s his latest, an Apple 2 rebuild, using his own TTL-constructed 6502.
(He’s a fan of using EPROMs for function lookup, which cuts the package count a lot, but of course uses lots (and lots) of transistors)
Matt describes this build as being about the same price and complexity as the Gigatron, but with a base of existing software.
In an earlier playlist he builds an SAP (simple as possible) CPU and makes reference to Ben Eater’s SAP series:
The SAP architecture comes from a textbook, available at the Internet Archive:
(another copy here)