Whether it has been described by others or is solely practiced by me I am not certain.
Warning: Over the years, this has, in a way, cost me the ability to perform mathematics and process "technical aspects" of life. I perceive consciousness, imagination, and "following the bliss" as paramount. The more I descend into this powerful, yet simple practice, the less value I project onto ordinary, restricted activities such as mathematics. (Although, paradoxically, this technique is more down-to-earth than any other if we assume the meaning of down-to-earth to be "tranquil in the moment.")
It's suitable for artists, for self-exploration, and for visualization in general. Here's how it works: Your visualization is already massive, infinite, and it's only being held down by your psychological constructs. That's all. The process you should apply when trying to visualize is to eliminate existing psychological boundaries. You are free to go anywhere, in any direction, to pursue the "w" axis of this world. When you usually try to visualize something, you are working upon preexisting framework of beliefs, which "slow the system down" if I may use the term. Each limiting belief is an axiom which clogs the mind. Attaining a powerful, transcendental visualization is simply about becoming aware of your limiting beliefs and dropping them down. What are the limiting beliefs in this case?
You believe that you reside in the third dimension. This is a mental construct holding your visualization down. Why? Because everything you visualize with this belief in mind will be subdued by and fall under the concept of "a third dimension". You believe that you are a human - this is another belief clogging the card's memory, which could be better used on visualization.  You believe that you are on Earth - this is another belief clogging the card's memory, which could be better used on visualization. When you let go of existing frameworks, your visualization will become a thousand times stronger. By default.
You are constrained by useful survival notions. They bombard you constantly - constantly (notice the word) - unless you become aware of them and let them go.
This is your golden ticket to Shangri-La; to visualizing and feeling whatever you need to. I use it in writing, but it can be applied in all sorts of fields.

For Purple I'd add shamans (unfortunately I don't know any specific ones)
It takes a real solid Yellow to see the healthy versions and also without judgment. @Leo Gura where would you put Immanuel Kant and Aristotle? Blue or Orange?
Here are some off the top of my head I'd throw out...
Stage Blue:
Marcus Aurelius  Socrates The Marathon Monks of Mt. Hiei Abraham Lincoln Confucius Chuang Tzu Stage Orange:
Tony Robbins Tripp Kramer (Tripp Advice) Sigmund Freud Sam Harris (he got me into enlightenment with the 26 minute guided meditation so I'll give him a shoutout for that at least) Renate Descartes Simon Sinek Stage Green:
Ram Dass Koi Fresco/Vishuddha Das Stage Yellow:
Mark Hyman Aldous Huxley Carl Jung (though he was peaking into Turquoise by the end of his life) Obama Stage Turquoise:
Shunyamurti  

This is what I have till now. You can add yours.
Stage Orange Role Models
Gary Vaynerchuk RSD Max RSD Tyler RSD Jeffy Todd Valentine Robert Greene Tai Lopez Ray Dalio Jack Canfield Bob Proctor Christian Guzman Thomas Frank  Shawn Thomas Patrick Bet-David Evan Carmichael David Goggins Jordan Peterson Tim Feriss Aaron Marino Arnold Schwarzenegger Kinobody Stephen Covey Napolean Hill Cal Newport Seth Godin Robert Kiyosaki Neil Strauss Coach Corey Wayne Dale Carnegie Brian Rose Will Smith Stage Green Role Models
Vishuddha Das Krystal Aranyani RSD Tyler RSD Julien Bob Marley Psyched Substance   Bill Gates Neil Strauss Richard Branson Stage Yellow Role Models
Joe Rogan Geoffrey Miller Leo Gura Jonathan Haidt Marting Seligman Mihaly Csikszentmihalyi Abraham Maslow Joseph Campbell Peter Ouspensky David Bohm Einstein Douglas Hofstadter Steven Pinker Noam Chomsky Don Beck Richard Feynman Jacque Derrida Michel Foucault Leonardo da Vinci Stage Turquoise Role Models
Sadhguru Leo Gura Mooji Shinzen Young Om Swami Adyashanti Stan Grof Ram Dass Wayne Dyer  Osho Don Miguel Ruiz Ken Wilber  David Deida Eckhart Tolle Byron Katie Marcus Aurelius Plato Epictetus Seneca Socrates Dr. David R. Hawkins Carlos Castaneda Peter Ralston Jed McKenna Alan Watts Martin Ball Gandhi Matt Kahn

As a life-coach myself, I recommend reading a few books on the topic first to get the general idea.
Now, certification is not required because it's a new profession. But you'll want to be sure to mind the boundaries between life-coaching and psychology. So, it's important to know the distinction.
But the certification and all that is not so important. There are only two things that are really important:
Can you do the job well? Can you ask questions intuitively to promote self-exploration? Can you find clients on a consistent basis? The latter is the real killer for most coaches.
Now, I make my living as a life-coach, ONLY because I had already created an international platform to find clients. I have a YouTube channel with over 30k subscribers. So, all I have to do is mention that I do life-coaching at the end of my videos to find clients. 
So, you'll want to set yourself up a social media presence through YouTube, Facebook, Instagram, or Twitter (or ideally all four) so that you can give away a BUNCH of free content. Give it for the sake of putting value out into the world. But also know that it's your bait and your net for getting clients. Use it as an opportunity to show your skills.
Life-coaching is not an easy sell anywhere. Very few make a living in the profession because they don't have a way to acquire clients. 
But if you build it, they will come.