The following is a list of people who have been mentioned (by either themselves or others) as potential candidates in 2020. Folks are on the list whether or not they have claimed or disclaimed any interest in running.

The list of people without government experience is followed by a list of current or past government officials who have been mentioned or have done something to suggest they are thinking about running for president.

Dwayne Johnson – Actor
Bob Iger – Disney
Howard Schultz – Founder & Exec. Chairman, Starbucks
Mark Cuban – Businessman and Owner, Dallas Mavericks
Kanye West – Entertainer
Mark Zuckerberg – CEO, Facebook
Oprah Winfrey – CEO, OWN (Only half struck out)

Andrew Cuomo – Governor of New York
John Hickenlooper (D) – Governor of Colorado
Steve Bullock (D) – Governor of Montana
Jerry Brown (D) – Governor of California
Martin O’Malley (D) – former Governor
Terry McAuliffe (D) – former Governor
Deval Patrick (D) – former Governor

Congressman John Delaney (D) – Announced 7/22/17
Congressman Luis v. Gutierrez (D)
Congressman Tim Ryan (D)
Congressman Seth Moulton (D

Cory Booker (D) – U.S. Senator
Amy Klobuchar (D) – U.S. Senator
Kamala Harris (D) – U.S. Senator
Bernie Sanders (D) – U.S. Senator
Kirsten Gillibrand (D) – U.S. Senator
Elizabeth Warren (D) – U.S. Senator
Chris Murphy (D) – U.S. Senator
Sherrod Brown (D) – U.S. Senator
Lincoln Chafee (D) – former Rhode Island mayor, governor, and U.S. Senator
Al Franken (D) – former U.S. Senator

Joe Biden (D) – former V.P., former U.S. Senator

Eric Garcetti (D) – Mayor of Los Angeles
Mitch Landrieu (D) – Mayor of New Orleans
Julian Castro (D) – Obama Secretary of HUD
Jason Kander (D) – former MO Sec of State/failed U.S. Senate candidate

Oprah Winfrey previously announced that she was not interested in running for president and then she gave a highly acclaimed speech at the Golden Globes. On the very evening of the speech, a variety of people encouraged her to run. Shortly thereafter a survey was conducted by Morning Consult from the 4th thru the 9th day after her speech. Here are the results.

59% of respondents say she should not run while 26% say she should.

Oprah bests Trump in a match up 40% to 36%.

And when she is matched against other potential nominees she beats the women and loses to the men.

Oprah 44% Gillibrand 23%
Oprah 39% Warren 35%
Oprah 37% Sanders 46%
Oprah 31% Biden 54%

Survey Monkey took a look at a portion of the field and found that if the democratic primary were held in January the result would have been the following:
Biden 22%, Sanders 17%, Warren 16%, Winfrey 16%, others 8%, Harris 7%, Gillibrand 4%, Booker 3%, Steyer 1%. [1/10-11]

Paired against Trump, the early results are:

Biden 57%/Trump 40%
Sanders 55%/Trump 42%
Winfrey 51%/Trump 42%

[CNN, 1/10/18]