Hackage, the Haskell community's repository of open source Haskell software
Hoogle, for searching the Haskell libraries and some of Hackage by name or by approximate type signature
Cabal, a tool for managing and installing Haskell software packages
Edinburgh Haskell Prelude, with facilities for pretty-printing user-defined algebraic data types and simplified types for some of Haskell's built-in functions
