This is as comprehensive a list of potential nominees as I can find, and I have sorted them into three categories, based exclusively on my own humble opinion. Some of them do not seem like serious candidates, but were included because there is talk about them, or they have expressed a desire.
Clearly establisment types:
Jeb Bush, Governor of Florida 1999–2007
Chris Christie, Governor of New Jersey since 2010
Lindsey Graham, U.S. Senator from South Carolina since 2003
George Pataki, Governor of New York 1995–2006
Bob Ehrlich, Governor of Maryland 2003–2007
Carly Fiorina, former business executive and nominee for the U.S. Senate from California in 2010
Mike Huckabee, Governor of Arkansas 1996–2007
John Kasich, Governor of Ohio since 2011
Peter King, U.S. Representative from New York since 1993
Mitt Romney, Governor of Massachusetts 2003–2007; presidential candidate in 2008; presidential nominee in 2012
Populist?Tea-Party?Anti-establishment?
Michele Bachmann, U.S. Representative from Minnesota 2007–2015; presidential candidate in 2012
John R. Bolton, U.S. Ambassador to the United Nations 2005–2006; Under Secretary of State for Arms Control and International Security Affairs 2001–2005
Ted Cruz, U.S. Senator from Texas since 2013; Solicitor General of Texas 2003–2008
Scott Walker, Governor of Wisconsin since 2011
Ben Carson, author and retired Director of Pediatric Neurosurgery at Johns Hopkins Hospital
Sarah Palin, Governor of Alaska 2006–2009; 2008 vice-presidential nominee
Rand Paul, U.S. Senator from Kentucky since 2011
Rick Perry, Governor of Texas 2000-2015, Lieutenant Governor of Texas 1999–2000; presidential candidate in 2012
Marco Rubio, U.S. Senator from Florida since 2011
Rick Santorum, U.S. Senator from Pennsylvania 1995–2007; U.S. Representative from Pennsylvania 1991–1995; presidential candidate in 2012
Donald Trump, business magnate and television personality from New York
Herman Cain, President of the National Restaurant Association 1996–1999; chairman and CEO of Godfather's Pizza 1986–1996; presidential candidate in 2012
Mike Pence, Governor of Indiana since 2013; U.S. Representative from Indiana 2001–2013
Mitch Daniels, President of Purdue University since 2013; Governor of Indiana 2005–2013
These folks were not easily categorized. They have all done some typical establishment stuff, but have also marched off doing their own thing too, not just taking direction from the Establishment. I think Jindal is the likely one from this category.
Jim Gilmore, Governor of Virginia 1998–2002; Chairman of the Republican National Committee 2001–2002; presidential candidate in 2008
Bobby Jindal, Governor of Louisiana since 2008; U.S. Representative from Louisiana 2005–2008
Susana Martinez, Governor of New Mexico since 2011
Rick Scott, Governor of Florida since 2011; former CEO and co-founder of Columbia Hospital Corporation
Rick Snyder, Governor of Michigan since 2011; former CEO and co-founder of Ardesta LLC
I expect 6 or 7 establishment candidates to run or at least start to run, and perhaps 5-6 from the other category. Both will winnow quickly, but there is a possibility that there is enough division in the establishment to get a real shot for one of the OTHERS!
I freely stipulate that everyone here will have their own opinion, right down to the "it doesn't matter" faction, but I thought it might provide interesting discussion.