My interests keep changing, I might be intensely interested in something because it came up in a book or movie, and then something else takes its place again, and it comes back up a while later.
As a child, things were: dinosaurs, the "Warriors" book series, books in general, certain Nintendo games, dragons, nature (animals, insects, plants), a certain manga series, broken limbs (weird, I know, but the amount of times I put a "cast" on my dolls or myself, or drew people with casts on can't be counted), and probably others I don't remember right now.
Now, as an adult, things are: still books, series/movies, mental health, random science topics (mostly from biology and physics), space science and astronomy, certain animals, geography/earth science (don't really know how to call it - random things, like geographic facts, natural phenomena such as Northern lights, vulcanoes and earthquakes), psychology and why people act the way they do, true crime, religious groups and sects (sometimes), medieval times, etc. etc. etc.
The list is long. The most consistent thing are books. I am very enthusiastic and can get immersed in a very wide variety of things.
The reason why I see them as "special" interests (I don't necessarily mean autistic "special interest" here, but also not "normal" NT interests) is that I get extremely immersed and excited about them for relatively short periods of time. I'll read a sci-fi book about space travel, and for the next 3 days, all I can think about is space. Then it's blown over and something else takes its place. The intensity makes them special for me, not the duration. Maybe that's an AuDHD thing? I'm not sure.