Some American history PODs:
1) Andrew Jackson is killed in the 1830s. If the assassination attempt where both guns misfired has one or the other fire and actually kill Jackson, then once the Nullification Crisis happens John C. Calhoun is President.
2)This next set lists Civil War generals killed IOTL battles whose survivals could change things as opposed to the cliche Stonewall Jackson:
John Reynolds
John Sedgwick
Patrick Cleburne (if he survives into Reconstruction given he advocated use of black Confederate troops)....
William Quantrill
3) A POD where William Henry Harrison's attack on Prophetstown miscarries due to say, a freak rainstorm or something and hence by the War of 1812 Tecumseh's coalition of Indian tribes is all together and united under a single leader much as was possible.
4) Zachary Taylor lives for his full term.
5) Huey Long is not assassinated.
6) Either MLK or Malcolm X die of old age instead of by gunshot.
7) One or the other of the GI Congressmen of the post-WWII elections is killed in WWII.
8) For the last one, a TL where William McKinley finishes both his terms.