@Lead here are my thoughts on your list:
Confirmed
John Delaney (US Congressman MD) (He has no chance. He just want the attention that comes with being first)
Possible
Joe Biden (Former Vice President)
(Best Chance of anyone on this list.)
Hillary Clinton (Former Secretary of State)
(Won't happen. Historically, Democrats don't back losers a 2nd time)
Bernie Sanders (Senator VT)
(His endorsement of Hillary Clinton would ultimately be his undoing. President Trump would be able to turn Hillary Clinton into a campaign issue all over again. Bernie would be in a position where he would either have to admit he was lying when he endorsed Hillary, or he will have to defend Hillary, either option will cost him votes.)
Elizabeth Warren (Senator MA)
(She has a 1/1024th chance of winning the primary. She's now a joke online, not a serious candidate anymore. She's gone as far as she can go in Government. The most she can hope for is a cabinet position from now on.)
Their stance on gun control makes them a complete non-starter in the Rust-Belt, South, and Mid-West:
Kamala Harris (Senator CA)
Andrew Cuomo (Governor NY)
John Hickenlooper (Governor CO)
Micheal Bloomberg (Former Mayor NYC/CEO)
Corey Booker (Senator NJ)
(His comical "I am Sparticus" moment puts him in the same position as Warren. He's gone as far as he's going to go in Government spare some cabinet position.)
Voters will read these names and collectively ask "Who?":
Kirsten Gillibrand (Senator NY)
Amy Klobuchar (Senator MN)
Sherrod Brown (Senator OH)
Steve Bullock (Governor MT)
(Even if some of you personally like these picks, understand that they lose to President Trump by name recognition alone.)
Terry McAuliffe (Formerly Governor VA)
(He has a better chance of being a VP candidate than anything else. The Democrats desperately need to hold Virginia in 2020. Unless a Virginian is on the ticket, they're going to have a hard time doing that.)
Eric Holder (Former US Attorney General)
(@Jack V Savage actually mocked me when I brought up the notion of Eric Holder running for President (I already know he'll pretend not to know what I'm talking about, doesn't matter). Eric Holder isn't running for President per-say. He wants the attention that comes with running for President so he can easily become the mayor of a major metropolitan city. You heard it here first.)
Julian Castro (Former Secretary of HUD)
(Being Hillary's VP reject isn't an actual qualification to be President. This guy got bit by the power and attention bug, and he wants another taste.)
Beto O'Rourke (US Congressman TX)
(Beto "Over the legal limit" O'Rourke won't even make it out of the primary. The revelations of his drunk driving only came out a few weeks before the election, otherwise the Democrats would have never supported him in the first place.)
Tulsi Gabbard (US Congresswoman HI)
(She has enough of a military record that she can actually challenge Republicans on foreign policy without looking weak. She would be an excellent VP pick.)
Oprah Winfrey
(She's not going to run. No private person especially wants the kind of scrutiny of their personal lives that comes with running for President. Most people like the attention that comes with talking about running for President.)