An alternate 2018 senate map if Hillary Clinton won in 2016.
In 2016, Hillary Clinton narrowly wins the presidency by eking out victories in Pennsylvania and Florida with margins of less than 1%, whilst losing Michigan and Wisconsin. Despite concerning comments made on the campaign trail, Trump concedes gracefully. Trump quits the Republican party as an independent, and spends the next year building the infrastructure for a populist media competitor to Fox News. To the surprise of many, Trump deletes his Twitter account to focus on running the new network, which has already poached talent from Fox News such as Tucker Carlson and Sean Hannity.
The 2016 Senate elections remain unchanged. Clinton enters the presidency in a very weak political position. The "blue wall" is on life support, Republicans control Congress, and the media focus on the email server investigation is pivoting to a growing scandal regarding the sale of American uranium to Russia during her tenure as Secretary of State. Her insistence of Russian influence on the Trump campaign falls onto deaf ears, as nobody believes a few sketchy Facebook posts could possibly influence an entire American election.
Republicans maintain control of the House, but earn a net loss of 5 seats thanks to changing demographics in suburban Texas. The House was barely expected to change, but a Republican net loss was not inconceivable because they already held a majority of swing districts with not much areas for improvement.
As for the Senate, the Democrats faced utter disaster because of an unpopular president combined with a historically awful map.
With Tim Kaine (D-VA) ascending to the vice presidency, civil rights activist Richard Spencer wins the special election for Republicans, as his "All Lives Matter" movement picks up steam following a massive peaceful demonstration at the University of Virginia with attendance of over 20,000. President Clinton harshly criticizes the demonstration, pointing out the Neo-Nazis in attendence, but the media and general public largely dismiss the white supremacists as a fringe minority that isn't reflective of the white men's rights movement. As for the scheduled Senate election in 2018, Republican Ed Gillespie easily defeats Democrat Ralph Northam.
Sen. Dean Heller (R-NV) is the only Republican running in a Clinton-won state, but is not seen as a serious pickup opportunity due to the sheer amount of defense Democrats are forced to play. He holds onto his seat by an eight point margin, suggesting he might have been vulnerable under a Republican presidency.
Sen. Jeff Flake (R-NV) emerges as a prominent anti-Clinton voice, criticizing her "immoral" presidency, earning him an easy re-election in a solid red state despite his opposition to Donald Trump two years prior.
Sens. Tester (D-MT), Heitkamp (D-ND), McCaskill (D-MO), and Donnelly (D-IN) retire in lieu of facing overwhelming odds in solid red states, and Republicans easily pick up those seats.
Governor Rick Scott (R-FL) ousts the incumbent Bill Nelson by a whopping 15 point margin, calling into question Florida's status as a swing state.
Senator Joe Manchin of West Virginia leaves the Democratic party, but does not caucus with the Democrats like Bernie Sanders or Angus King. Former CEO and convicted felon Don Blankenship wins the Republican nomination, but Manchin easily cruises to a victory, thanks to his strong independent branding and suppressed Republican turnout.
President Clinton appointed Sen. Kirsten Gillibrand (D-NY) as Secretary of State, due to their close relationship and the view that a New York senate seat would be an easy Democratic hold. Governor Cuomo appointed Democratic Rep. Joe Crowley to fill the vacancy (whose House seat is filled by a little-known bartender), but in a stunning upset in the Democratic Primary, Crowley loses to TV personality and civil rights activist Al Sharpton. Sharpton's anti-Semitic comments from the 1980s come to light, prompting a mass defection of the Jewish vote to the Republican party. Sharpton's support for reparations and some high profile disputes with the NYPD causes Democratic support to plummet everywhere in the state, save for a few gentrified districts in Manhattan and Brooklyn. Despite all this, Sharpton was seen as a favorite to win the election due to New York's heavy Democratic lean. Republican Rep. John Katko runs an underfunded campaign, but pulls off an upset victory by 2%.
Sen. Bob Menendez (D-NJ) is indicted on federal corruption charges and is subsequently found guilty at trial. Menendez refuses to resign, even whilst he awaits sentencing. The Senate expels him in an overwhelming 99-0 vote (Sen. Cory Booker abstains), the first expulsion since the Civil War. With the New Jersey Democratic party in shambles due to the Menendez scandal, Chris Christie wins the senate election against Jon Corzine in a rematch of the 2009 governor race.
President Clinton appoints Sen. Al Franken (D-MN) as Secretary of Defense, in the most contested cabinet appointment of her presidency. Republicans criticize his lack of military experience, arguing the only reason he was appointed was because of some pre-existing backroom deal. Franken is approved by the Senate by a 51-50 vote with Vice President Kaine breaking the tie along with a few moderate Republicans voting in support. The two Minnesota Senate elections has incumbent Amy Klobuchar (D-MN) winning in a tighter than expected race, whilst former governor Tim Pawlenty (R-MN) wins the Senate special election.
In the only bright spot for Democrats in the Senate, incumbent Ted Cruz (R-TX) narrowly loses to insurgent congressman Beto O'Rourke. O'Rourke's charisma and support from the growing urban centers pushes him over the top. In a surprising twist, Donald Trump throws his support and rallies his base behind O'Rourke, not because he agrees with his policies, but because Trump blames Cruz's insistence on dragging out the presidential primary for his loss in the general election. Cruz's loss arguably demonstrates the huge amount of political influence wielded by Donald Trump, even after losing the presidency.