Looking for a word that describes a little known but nevertheless influential person, group, etc

Question

Heard an old joke about someone trying to namedrop. The person they were talking to didn't know who they were talking about, so they said, "Well, they really are very famous, even though most people don't know who they are."

But there's a kernel of truth in that old joke, namely that someone not all that well known can still be very influential, though they are by definition not very famous. Further, certain people really like the idea of knowing people like this, since it makes them feel like they are "in the know". I'm not talking about conspiracy theories, like the Head of the Bilderbergers or Masons or something. I mean, perhaps there is some fashion designer that fashion designers are all copying, or some music mogul who pretty much decides what the next pop music style is going to be. And then the internet is rife with urban legends of people who can build up a product's brand through anonymous viral marketing.

Is there a single word for people, organizations, what have you, that fit this description?

Answer 1

You might be thinking of an influencer, although that doesn't necessarily imply the quality of being unknown that you're looking for.

influencer

NOUN

1. A person or thing that influences another.

   ‘he was a champion of the arts and a huge influencer of taste’
   ‘genetic factors are key influencers of your metabolic rate’
   ‘Frank's been a teacher and cultural influencer for years’

   1.1 Marketing A person with the ability to influence potential buyers of a product or service by promoting or recommending the items on social media.

   ‘influencers can add serious credibility to your brand’

(From the Oxford Dictionaries)

So perhaps what you're really looking for, with the secrecy added in is a puppetmaster:

puppetmaster

NOUN

A person, group, or country that covertly controls another.

‘the puppetmaster behind the current administration’

(From the Oxford Dictionaries)

There is also the notion of a shadow government, wherein the elected government does not have any real power; that power lies with the secret shadow government. I'm not sure if there is a term such as shadow influencer, but perhaps this will trigger a memory for someone else.

Answer 2

I am not aware of a single word which describes this concept, but I have often heard of individual people fitting that description described more succinctly as "famous in [one's] field".

Answer 3

Trendsetter

a person or thing leading the way in fashion or ideas

Mark Burnett, better known as the creator of Survivor, was a trendsetter for reality shows.