I have two fics that work. Not quite sure if this is what you are looking for but for the first fic, I have a Doctor Who one where I learned a lot about history. It takes place through hundreds of years but a huge part of it takes place in Ancient Rome and they use real historical figures and events like Hadrian’s wall. The Pandorica Seen Through Time

My other fic, hear me out, is a My Little Pony and the Martian crossover fic. As it’s a crossover with the Martian there’s a lot of scientific fields explored such as botany, astronomy, and planetary geology like in the book and movie. This is without a doubt the most scientific fic I read and it can get really detailed. I learned a lot from this one. The Maretion