I'd say the whole game of eDSL creation is an act of metaprogramming. There are examples littered everywhere in the Haskell world—though rarely do syntax abstractions like macros get used. This is because it's relatively easy to embed a natural style program in a monad or applicative functor, access the syntax, and compile it.

A smattering:

http://hackage.haskell.org/package/accelerate https://github.com/mainland/nikola http://hackage.haskell.org/package/esqueleto http://hackage.haskell.org/package/api-tools http://hackage.haskell.org/package/atom http://hackage.haskell.org/package/diagrams http://hackage.haskell.org/package/c-dsl https://hackage.haskell.org/package/js-good-parts http://hackage.haskell.org/package/Bang http://hackage.haskell.org/package/orc

And if you buy that definition, then there is some ungodly metaprogramming available in dependently typed languages.

https://github.com/pigworker/MetaprogAgda/blob/master/notes....

Though, to be clear, there are few who can follows those notes today.