[jeremiep]

xmonad also comes to mind.

But you're talking more about products than programming languages. Haskell contributed a LOT to programming theory.

Your every day coding is most likely using things coming directly from Haskell without you knowing it.

[jbeja]

jQuery and Javascript Promises comes to mind, I know they started in C++ put they are practically Monads.

[saosebastiao]

Since when did monads become a synonym for Haskell?

[Retra]

You really need to learn monads to use Haskell, and it's one of the major barriers for newcomers. It's no different from pointers in C.

[coldtea]

Since 2000 tutorials emphasizing them as the gist of Haskell programming...

[rubiquity]

I think you mean one specific kind of a Monad.