I bought a fantasy novel recently that was written in 1998. Turns out the author wrote 11 more novels in this series which was a big part of why I chose it. The most recent novel came out in 2021. She no doubt will receive a tiny amount of income in 2022 from my purchase in 2022 stemming from work she completed in 1998. I would classify that as passive income but of course is it really? Would the book have even been on the shelf at Books A Million if she has stopped writing in 2000? Hard to say but I think most people would consider that passive income earned this year.