Basic Typeclassopedia
Functor
Applicative
Foldable, Traversable
Monads
Other (Arrow, etc.)
Advanced types
Algebraic data types in depth
Advanced Type classes
Type families
GADTs
Debugging and code optimizing
Strictness in data types and functions
Memory and CPU profiling
Efficient data structures (bytestring, text, vector and co.)
Note on "unsafes"
Understanding the Runtime System
Memory layout in GHC
Unpacking strict fields
Understanding and reading Core
Concurrency in Haskell
Haskell threads
MVars and co.
STM
Parallelism
Foreign Function Interface
FFI basics
Safe vs. unsafe
Globals in Haskell
Template Haskell
Splicing and quotation
The Q monad
Reification