I have listed all the people I can think of who have been seriously mentioned as contenders. Let's start with who it won't be, and work our way from least to most likely of those who have been suggested:
OUT OF THE RUNNINGMichelle Obama (56)
Forget about it.
Hillary Clinton (72) - Former First Lady, Senator & Secretary of State
The biggest issue I see with Hillary, apart from all the baggage, and the objections that would have to be faced down, is that Hillary and Joe are so similar. Their positions would be in sync, which helps, but they are strong with the same groups of voters (older / liberal / educated / Black / Southern, New York, Cali), so she doesn’t really add many he wouldn’t already get - maybe some women. The last time there was a pairing who were so similar was Bill and Al Gore. Bill took criticism for his identikit selection (both young Southern centre/left liberals), instead of adding someone older or from the North / Mid-West. He said he picked Gore for his foreign policy experience, environmentalism and strong family values (not areas that Clinton was known for). They pulled it off by selling it as a new generation (they are the youngest team ever elected), but it still seems unnecessarily risky by Clinton. Biden's landslide lead potentially gives him the freedom to pick anyone he feels like and Hillary would definitely fulfil both of his requirements (simpatico with his beliefs and objectives and ready to be Prez), but it's just not going to happen.
Kirsten Gillibrand (53) - Senator, New York
Gillibrand has been in the Senate since 2009 and has had a remarkable transition from being quite right-wing when she was in the House (2007-2009), to being quite liberal now. She ran for President, but that didn't go as well as she might have expected and she dropped out very early. I was expecting to see her at least in the running for VP (and she did mention last year that she would be interested), but it seems she set her sights on being Sec of Defence. She is very hot on #MeToo (and was largely responsible for forcing Al Franken, one of the Dems rising stars, to resign his seat after a fairly innocuous joke and some accusations that fell apart later). It seems that she is appalled by the military's approach to sexual harassment etc and wants to shake it up. I'd have thought the President would want someone in that role whose primary focus is keeping the country safe.
Stacey Abrams (46)
Stacey led the party group in the Georgia House of Representatives for five years, before running for Governor and being cheated out of the win by the evil Brian Kemp who oversaw the election, in which he was a candidate, as part of his previous role as Georgia Secretary of State, and got away with blatantly rigging it. She has faced some of the same issues as 'normal people', being severely in debt for a few years, including at the time of the election for Governor, mainly from paying for her parents' healthcare, though she also had a bad credit card habit. She has paid it all off, having access to sources that most don't, mainly through her novels and soft porn writings.
Over a year ago, just before Joe's candidature was announced, Axios reported that he was considering coming straight out of the gate with a pre-announced running mate, ie Abrams, and all the networks ran with it. Clearly it didn't happen, probably because limiting your options so early would be bonkers, but the fact that Abrams was the one under consideration seems hard to believe. She is seen as extremely left wing by many - a ray of hope for some and of terror for others, though she made substantial compromises in the Georgia House to get things done, which sullied her leftist credentials in the eyes of some. Although flexible with her beliefs when required, she just starts out from too different a starting point for Joe.
She is unique in being completely open about the fact that she was actively campaigning for the VP slot and she promoted herself and the case for a black woman on the big shows on all the networks. There was a funny-but-sad joint interview with Biden in May, where she appeared to think he was about to announce for her right there and then, and you could see her soul leaving her body as it quickly became apparent that the interview itself was her reward and the praise Joe was dropping on her was all she was getting.
Amy Klobuchar (60) - Senator, Minnesota
Amy didn't start as favourite for VP, but she was always in the running. Her momentum kept building after her very impressive performance in Presidential Primary debates, and as cracks appeared in Kamala's image. They have similar baggage, both having been Attorney General of their State, so will have created certain groups who resent them for doing that job, as well as some who claim miscarriages by them. However, Amy is hugely popular in Minnesota, which is right in the key Mid-West region where Biden needs success in neighbouring States. Apparently, Joe was surprised and impressed that she brought in the State for him on Super Tuesday and his wife is known to like Amy. There was a lot of pressure for a Black running mate, but messages started to come out that it wasn't going to happen. Network anchors started reminding us that Joe was already very popular with Blacks, so already had a lock on their vote. The message was leaked repeatedly that the Black constituency would be given Attorney General, in the person of Kamala, and that Amy would be VP. For a couple of weeks, this was the settled position.
Then George Floyd happened. For this to explode in Minnesota was enough to rock Amy's chances. When it came out that she had personally decided not to prosecute the policeman involved for a previous incident, thereby allowing him back onto the streets in uniform, she was toast. The timing was just so terrible for her, coming right at the height of the VP speculation. And that was that. She made a statement withdrawing from the race, saying that she had told Biden that the job should go to a woman of colour. This wasn't for her to say, so it may have been at Biden's suggestion, but it was generally taken as a stab in the front for Elizabeth Warren, the other leading White contender. Warren is the only serious contender from the progressive wing, and it was assumed that Amy was trying to make it harder for her to be selected for that reason as much as the racial thing.
Tammy Baldwin (58) - Senator, Wisconsin
Wisconsin will be one of the key States in the election, so Baldwin could be pivotal. However, as the first gay person in the Senate, she may encounter opposition in some area, but get bonus points in others. Probably more importantly, if she became VP, that would lead to a bye-election and, as it's Wisconsin, it's not guaranteed that the Democrats would keep the seat. There was some talk about her, but it has died down.
Gretchen Whitmer (48) - Governor, Michigan
Whitmer got a lot of coverage during the lockdown protests and was perceived as performing very well by the Democrats, and horrifically by conservatives. She has very high ratings in Michigan, despite what the TV images of the protestors might suggest. Michigan is one of the swing States that Biden may need to win and, at one point, she almost seemed to be becoming favourite for the role, but the continual bashing by Fox did seem to damage her image nationally. Whitmer has said outright that she is focused on her work in Michigan and is not interested in the VP job, which I initially took with a pinch of salt, as they all say that, but she seems to have gone right out of the reckoning now.
Jeanne Shaheen (73) - Senator, New Hampshire
Maggie Hassan (62) - Senator, New Hampshire
You never heard of them, right? They are the only two women in history to have been both Governor and Senator, and they're from the same State. Joe unexpectedly named them both as being under consideration a while ago. This seems to be him just giving a bit of recognition to people he admires, which is all very nice, but a waste of everyone's time, as they can't seriously be in contention. Shaheen quickly said she's not interested, though Hassan would be. Their Senate seats would also be at risk in a bye-election. You can forget about them again.