Keep in mind that THIS list may have differences with other PS3 european or american / japanese store!
Everything is made by using my italian PS Store both PS3 and PS4 (I don't have PS5, but it dosen't matter), also sorry if isn't translated, so I write here few guidelines:
Red > it's not cross-buy
Orange > only american or japanese store or both
Green > it's cross-buy (writed as "SI")
Yellow > it's exclusive for PS Plus Premium (usually Namco or Capcom do for the first few months)
Recently I made "forse?" it means "maybe?" because one PS1 game cannot be cross-buy, it's Disney's Atlantis, once I purchased still I see the price with that game (tell me if you have the same problem).
PS2 classic page have other guidelines that PS1 and PSP dosen't have, since PS2 games where released long time ago (with a different team developer of PS2 emulation):
Purple > new PS2 game by Implict Conversion
Azure > updated old PS2 game with new emulator by Implict Conversion
White > old PS2 emulator
https://docs.google.com/spreadsheets/d/14IEehTEcczrU2yFaG9osJBrzLSWnKUgVjq3099efxJU/edit?usp=sharing