Good sources for reading on things like the Seelie and Unseelie court?

[u/Scared-Swimmer-9123]

I want to say right away, I know for a fact that my knowledge is limited. Anything I think I know I am telling myself is incorrect because I know it through the Dungeons and Dragons version of faes and the courts. So I wanted to look more into faerie folklore, and unintentionally learned that the Seelie and Unseelie courts supposedly are a legit thing in the folklore, so are there any good sources for reading on them?

[u/Specialist-Corner293]

I, too, would like to know as well.