Too much interesting haskell stuff on the web. Difficult to keep track so posting all of that here:
https://ghc.haskell.org/trac/ghc/wiki/Commentary/Rts/Storage/HeapObjects
https://ghc.haskell.org/trac/ghc/wiki/Commentary/Rts/STM
Yampa: https://pdfs.semanticscholar.org/5a55/13560ef9bdc444c781ad15c3e44558492759.pdf
https://www.schoolofhaskell.com/user/bartosz/understanding-yoneda
System FC: https://pdfs.semanticscholar.org/b49e/9c2d00acd25ada608170c3c3485880261980.pdf
https://www.dcc.fc.up.pt/~pbv/aulas/linguagens/peytonjones92implementing.pdf
https://www.microsoft.com/en-us/research/wp-content/uploads/1992/01/student.pdf
http://library.readscheme.org/page1.html (The original Lambda Papers by Guy Steele and Gerald Sussmann)
SICP Chap. 4 and 5 (Non Haskell but FP nonetheless)
http://blog.sumtypeofway.com/an-introduction-to-recursion-schemes/
https://medium.com/@jaredtobin/practical-recursion-schemes-c10648ec1c29
http://okmij.org/ftp/tagless-final/index.html
http://okmij.org/ftp/Haskell/zseq.pdf
http://okmij.org/ftp/Haskell/Reflection.html
https://arow.info/blog/posts/2015-07-10-servant-intro.html
https://blog.jle.im/entry/practical-dependent-types-in-haskell-1.html
https://blog.jle.im/entry/practical-dependent-types-in-haskell-2.html
http://okmij.org/ftp/Computation/free-monad.html
http://blog.ielliott.io/continuations-from-the-ground-up/
https://www.twanvl.nl/blog/haskell/cps-functional-references
https://github.com/lotz84/haskell/blob/master/docs/monad-transformers.md