contributor
noun
Definitions
A benefactor; someone who donates to charity or some cause.
Example: I am a longstanding financial contributor to Amnesty International.
A person who backs, supports or champions a cause, activity or institution.
Example: He was a regular contributor to Greenpeace protests.
A person (or thing) instrumental in the creation or growth of something.
Example: With her strength and intelligence, she was an important contributor to the victorious effort.
A person who produces articles published in a newspaper, magazine, online publication, etc.
Example: William Safire has been a notable contributor to the op-ed pages of the New York Times for many years.