When compiling a who's-who list of potential 2016 presidential candidates, look no further than Virginia.

There, a coterie of Democratic and Republican hopefuls are trotting out onto the campaign trail for their respective gubernatorial candidates, Democrat Terry McAuliffe and Republican Ken Cuccinelli.

Former Secretary of State Hillary Clinton kicked off her public involvement in the race when she stumped for McAuliffe on Saturday, after having hosted a handful of fundraisers for her close friend in Washington. She and her husband, former President Bill Clinton, plan to make a combined 12 public appearances before Election Day on behalf of McAuliffe, a top fundraiser for Clinton's presidential campaigns, a campaign aide confirmed.

On the Republican side, Sen. Ted Cruz, R-Texas, partnered with Cucinelli for a fundraiser, and Rep. Paul Ryan, R-Wis., joined the gubernatorial hopeful on a conference call to bash Obamacare. Cuccinelli is trailing McAuliffe in the most recent polls.

McAuliffe might soon have more star power on his side. Vice President Joe Biden is seriously considering campaigning in Virginia on McAuliffe's behalf, a McAuliffe aide confirmed. Vouching for McAuliffe in the important swing state of Virginia could also boost Biden in 2016 should he choose to seek the Democratic nomination for president.

Maryland Gov. Martin O’Malley, another potential contender for the 2016 Democratic nomination and an ardent Clinton supporter, said Thursday that he is considering campaigning for McAuliffe but has not decided yet — in large part because a Maryland governor might be ill-received in some parts of Virginia.

“There’s all that weird rivalry stuff that goes on between the two states,” laughed O’Malley, who raised money twice already this year for McAuliffe and who has exchanged snarky comments over the years with Virginia Gov. Bob McDonnell.

Giving McAuliffe and additional shot of attention is a guy who has expressed no interest at all in running for president in 2016 or at any other time: Musician will.i.am, who earlier this year gave $100,000 to McAuliffe's campaign, and who is coordinating with McAuliffe staff about potential appearances on the campaign trail.