I'm having trouble finding anything concrete online (other than people simply repeating the folk wisdom) other than control flow operators, which are implemented as normal functions in Haskell (i.e. including custom control flow operators).[0] Although, one Reddit comment[1] did also mention typeclasses as obviating other types of macros, so I've edited my earlier comment accordingly.

[0] https://www.reddit.com/r/haskell/comments/5xge0v/comment/deh...

[1] https://www.reddit.com/r/haskell/comments/1929xn/comment/c8k...