Unlike the other comments so far, I have a link that is in my opinion NOT generally useful for most programmers. I figured it is worth a share for the programmer who knows all of the math in this post and wants to learn yet more:
I'm interested in learning about category theory in general just to get a feel for the subject, but I also want to have a better concrete understanding of the category theory that is put to use in Haskell.
Category Theory by Steve Awodey is great, but in my opinion only for a graduate mathematician wanting to do more mathematics and understand category theory in an abstract sense. Preferably one will have done some algebraic topology when reading it.
Category Theory for Programmers is just that, for programmers. In fact, if I recall correctly its preface explicitly answers the question 'Why write this when Category Theory by Steve Awodey exists?', with the answer being what I summarise above. If you're a computer scientist, programmer, or otherwise a non-mathematician first, Awodey is not for you and this book I believe should serve you very well instead. I haven't read it, mind.
I haven't come across Seven Sketches in Compositionality, but hopefully that helps compare the other two. It's mostly about your intention (e.g. theoretical mathematics vs practical application) and background.
https://bartoszmilewski.com/2014/10/28/category-theory-for-p...
Other people can debate category theory's utility: I have no expert insight of my own to lend.