contributor

noun4

1. •
   A benefactor; someone who donates to charity or some cause.

   • I am a longstanding financial contributor to Amnesty International.
2. •
   A person (or thing) instrumental in the creation or growth of something.

   • Methane is a major contributor to global warming
3. •
   A person who backs, supports or champions a cause, activity or institution.

   • He was a regular contributor to Greenpeace protests.
4. •
   A person who produces articles published in a newspaper, magazine, online publication, etc.

   • William Safire has been a notable contributor to the op-ed pages of The New York Times for many years.