Even if he's a younger guy than most other examples, my mention is:

Jordan Walke

He's the inventor of React, which probably changed the way to write (web-)apps for a lot of people and was based on a prototype written in StandardML.

He's also created ReasonML which is not only in many ways a more fitting language to write React, but also a good systems language (props to OCaml and it's unbreakable type system). Many React concepts/patterns have their origins in functional language concepts, including reducers and hooks.