Is there an encyclopedia/list of common type classes in Haskell?

Question

Is there any website that lists and describes common type classes in Haskell?

Answer 1

The Haskell 98 Report lists the predefined types and classes.

If there's a library type you're interested in, you might want to start at the Haskell Library Contents or Index.

Answer 2

You might find "The Typeclassopedia" by Brent Yorgey (published in issue 13 of 'The Monad Reader') helpful. From the abstract:

The standard Haskell libraries feature a number of type classes with algebraic or category-theoretic underpinnings. Becoming a fluent Haskell hacker requires intimate familiarity with them all, yet acquiring this familiarity often involves combing through a mountain of tutorials, blog posts, mailing list archives, and IRC logs. The goal of this article is to serve as a starting point for the student of Haskell wishing to gain a firm grasp of its standard type classes. The essentials of each type class are introduced, with examples, commentary, and extensive references for further reading.