I've done a couple of Atari 2600 projects in the past: my Pong clock and my Enigma Machine simulator. To make physical realizations of these projects, I relied on some boards that I bought a few years ago from AtariAge, but when I checked a few months ago, it appeared that they had stopped selling them in their store. It wasn't a big deal, but I did consider the fact that at some point I might want to have some more PCBs for future projects.
Luckily, the guys at Grand Idea Studio did all the heavy lifting, and have PCBs not just for the Atari 2600, but also many other classic video games systems, including schematics and Gerber plot files. Archived for a future project.
Pixels Past Circuit Boards | Grand Idea Studio.