Q: tl;dr
A: There are probably games that were released physically that you don't know about. Find them here.
Q: What is the "master list"?
A: The master list is a catalogue of all the games that have been identified here that meet certain criteria that differentiates them from standard, mainstream releases. It offers information regarding regional exclusivity, retailer exclusivity, print quantities and more.
Q: What are the criteria? How do you decide which games make the list?
A: For the most part, these will be "smaller" titles that were originally released as digital-only but have been given a physical release. Some exceptions may apply, like if an indie game launches with a physical release, it will likely be listed. Another exception would see a larger title that was only released digitally, for whatever reason, get a limited physical release (example: if Limited Run Games did a print of Fatal Frame V.)
Generally if a game is, as the title says, indie, limited or obscure and has a physical release, you'll see in on the "master list."
Also, the game must be region-free or NTSC-U and in English (subtitles are valid).
Q: Region free or NTSC-U? Doesn't that mean the list is only valid for North American users?
A: This means that every game on the list will be playable on North American consoles, though a few games may have versions that are region-locked on a certain console (this will be noted). Most games are now region free, so if you aren't from the NTSC-U region, it's very likely that the game will work for you. Knowledge of which systems do and don't have region-locking should allow anyone to make use of this list.
Q: What about games for collectors who aren't in the NTSC-U (North American) region or own consoles that can play region-locked games?
A: There may be a separate tab for you guys down the line. One step at a time.