On Facebook I've jokingly commented "Michelle Obama / Corey Booker 2024" but that's not really a viable ticket, just because Booker's still a relatively junior Senator and Michelle Obama has not held a political office as of yet. Sanders will be in his 80s by then.
Governor Mark Dayton of Minnesota, though, could be a good contender. Help draw in the Middle America that feels abandoned, his tenure as governor has been relatively successful, not a lot of scandals that I've heard of involving him.
Maybe Representative Michele Lujan Grisham as a balance - young, from a prestigious NM political family, big on health care reform and issues effecting the elderly, considered a real up and coming Latinx politician.