1888: William McKinley/Benjamin Harrison (Conservative National Party) 
1888 def. Grover Cleveland/Adlai Stevenson (Liberal Democratic-Whig)
 While English was a popular president, He had announced he would not stand for a second term, So, the LDWs nominated Grover Cleveland to run as their candidate in 1888, however, Cleveland was an unpopular man who just barely retained his House seat 2 years earlier. Meanwhile the recently formed Conservative National Party nominated Representative William McKinley as their candidate, the campaign was tiresome, Cleveland didn't campaign personally and often sent advisors to do it for him, when Election Day came, McKinley won in a landslide.
Nice footnote. Could I make one suggestion (and just a suggestion!) - Rather than have William McKinley/Benjamin Harrison as a Conservative National Party, why not have them as the Liberal-Democratic Whigs (which is I think already a more Conservative Party in this time line)? It seems more likely that the conservative element of the party would ascend internally as opposed to a new third party (which hasn't been mentioned previously) gaining power. Also, if you could give a sentence or two to the policies of the President, it would help create a picture of the world. No offense meant, I don't want to become the person who criticizes everyone's updates!
List of currently active collaboratively created leaders lists
- List of US Presidents 1960 - 2020 - What if the Whig Party remained a major Party in the United States?
- List of U.K. Prime Ministers 1945 - 2020 - TL#1 What if there were only single or non-concurrent term Prime Ministers? / TL#2 - What if the U.K. had been invaded by Nazi Germany and then liberated by the USA? [Feel free to update 1 or 2 or both!]
- List of German Chancellors (1949 - 2030) - No theme, the inaugural list!
- List of Prime Ministers of Canada, Australia and New Zealand - new thread!