I would have expected a little longer wait before this would have shown up on Wikipedia, or at least a shorter list. But here we have long articles on the endorsements to date in the Democratic and Republican campaigns for president - endorsements from political figures, organizations, celebrities, news media and more. They're extensive lists.
On the Republican side Jeb Bush and Rand Paul seem to be fighting it out for the longest lists, but just about all of the candidates have someone. Among those that caught my attention: radio shouter Michael Savage for Donald Trump; Dave Mustaine of the band Megadeath for Rick Santorum; Oracle CEO Larry Ellison for Marco Rubio; John Stossel and Geraldo Rivera for Paul; just one (a New Hampshire state senator) for George Pataki; Chuck Norris and Tony Orlando for Mike Huckabee; John McCain for Lindsey Graham; Adam Carolla for Ted Cruz; musician Kid Rock for Ben Carson (the only endorser listed for him); businessman T. Boone Pickens for Bush.
There's a longish list for Hillary Clinton on the Democratic side, maybe in part because she still has such a presumption of getting the nomination. There's a long list of actors, singers and others in the entertainment area, and businesspeople from Warren Buffett to Larry Flynt. Her competitor Bernie Sanders has a fair-sized list too, though. His backing from Portland radio host Thom Hartmann, singer Neil Young (made famous in his recent dustup with Trump), musician David Crosby, comedian Lewis Black, radio host Ed Schultz, writer Matt Taibbi, and among organizations (though I'm not clear how they organized enough to endorse anyone) Occupy Wall Street.
Anyway, the lists are there. Check 'em out.