mtl-style-example VS scrabble

Re: effects libraries, it's probably worth starting with e.g. https://www.fpcomplete.com/blog/2017/06/readert-design-pattern/ https://www.parsonsmatt.org/2018/03/22/three_layer_haskell_cake.html https://github.com/lexi-lambda/mtl-style-example if you're just getting familiar with the ecosystem. I'll add, anything written by the the people I linked to in this comment is probably worth reading as well.

Personally, it felt to me like, once I really understood monad transformers (https://hackage.haskell.org/package/transformers) and mtl (https://hackage.haskell.org/package/mtl), the reasons they both exist and how they are distinct, how you use them generally and what common patterns are around structuring your app (see e.g. https://github.com/lexi-lambda/mtl-style-example and the 3-layer-cake link someone else provided here for two), a lot of stuff in the ecosystem suddenly became comprehensible and useful to me, in a practical, "real world" way. In fact I'd go so far as to assert that getting comfortable with mtl in particular is the biggest single step you can take to being able to build arbitrarily useful real-world apps that are no longer toys.

I wrote this Scrabble tutorial for uni students at the same sort of stage as you. Maybe they're a tiny bit further on but you should find it pretty self-contained. It includes a CLI with a curses lib so you would learn how to do that.

In case it's useful, here's a tutorial of mine that gets into creating a library and a couple of frontends for playing a board game, mostly using "boring Haskell" but exposing some useful patterns and touching on widely used libs for JSON, lenses, websockets etc https://github.com/jimburton/Scrabble