I think if you had a subscription to qore (the video magazine on ps3 pre +) they gave out some ps1 games. I have spyro, wild arms, and siphon filter and I know I never bought them.
It's strange, I just noticed that when I look at my library on PS5 when you go to the option to sort by you can do it by platform and PS3 is listed but no results show up. It would be a pretty big oversight to have anything even mentioning PS3 is there wasn't a plan for it. At least that's my...