Parsers

More info here: http://book.realworldhaskell.org/read/using-parsec.html

Monads

https://github.com/afroisalreadyinu/real-world-haskell-chapter-10

Next steps

Typeclassopedia, which is part of the Haskell wiki (found at https://wiki.haskell.org/Typeclassopedia)."
to parallelize Haskell code. Read Parallel and Concurrent Programming in Haskell (O’Reilly Media, 2013), by Simon Marlow,
Idris and Liquid Haskell, more powerful type system than haskell,
Manning has published a book on Idris by the creator of the language: Type-Driven Development with Idris by Edwin Brady (2017).

Clojure : on jvm, has access to Java functions
Peter Seibel’s Practical Common Lisp (Apress, 2005), which is available free online: www.gigamonkeys.com/book/.

ML family of languages,

http://fsharp.org/.
Scala : on jvm "probably your best bet if you’d like to do functional programming for a living"
Elm (http://elm-lang.org/) and PureScript (www.purescript.org) similar to Haskell can be compiled to JavaScript

"The Elm programming language is focused on creating JavaScript user interfaces using functional programming"

"PureScript is focused on making a Haskell-like language that compiles to JavaScript"

PureScript is very similar to Hasell in syntax.