When it comes to history, I lean towards “trends and forces” over the “great man” theory. I’d like to test this. Do you have recommendations for people or especially specific media that would challenge my view?
Some clarifying examples:
– Neither Sabin nor Salk get credit for curing polio, because if one of them hadn’t the other one would have, and if neither had someone else would have. Obviously developing the vaccine faster was a big deal for the kids who would otherwise have caught polio in 1956, but it’s not changing the trajectory of the world.
– Robert Moses may count as a Great Man because he locked NYC into a car-based equilibrium that people are unable to break to this day. In general I think “moved world to a different equilibrium” is going to be a common pattern among people who change the world.
– Dictators killing a bunch of their own people doesn’t count, the effect is too local.
– There’s a reasonable argument John Wilkes Booth counts because Lincoln would plausibly have handled Reconstruction much better than Johnson. But if I learned there were many planned attempts on Lincoln’s life and estimate at least one would have succeeded, Booth would no longer count.
– To the best of my knowledge, whoever started the American civil war doesn’t count, because that was pretty clearly going to happen. But both Grant and Lee do count, because who won the war mattered and there weren’t equally skilled replacement generals. We know this because the north tried 400 people before Grant.
Aceso Under Glass 
Muhammed and Jesus (or perhaps Paul?) come to mind as people whose influence caused major changes, and where equilibrium isn’t the right lens.
LBJ was plausibly crucial for making civil rights happen in the US.
I don’t know the details, but my rough understanding is Ashoka introduced a lot of liberal reforms because he thought they were a good idea (https://en.wikipedia.org/wiki/Ashoka).
Unclear that Buddhism would have arose if Gautama Buddha hadn’t had the particular insights he had (https://en.wikipedia.org/wiki/Gautama_Buddha).
Genghis Khan’s empire caused a lot of cultural exchange between Asia, Middle East, and Europe that probably wouldn’t have happened if he hadn’t united the Mongol tribes. See: https://www.goodreads.com/book/show/93426.Genghis_Khan_and_the_Making_of_the_Modern_World
LBJ was plausibly critical for making civil rights happen in the 1960s. See Caro’s biography.
Ashoka instituted a bunch of liberal reforms basically because he thought they were a good idea (I don’t know the details here).
Buddhism probably wouldn’t have happened when it did without the particular insights that Gautama Buddha had when he had them.
Genghis Khan’s empire was responsible for a lot of cultural mixing between Middle East, Asia, and Europe that probably wouldn’t have happened if he hadn’t united the Mongol tribes. See https://www.goodreads.com/book/show/93426.Genghis_Khan_and_the_Making_of_the_Modern_World
Stalin (while a terrible human being) was probably crucial in leading to an allied victory in WWII. There were many policy rifts in the Soviet Union’s leadership prior to the war and Stalin’s faction favored industrialization mechanization and ramping industrial capacity at almost any cost. Other factions did not have that same focus or those same goals. A Lenin or Trotsky controlled Soviet Union probably loses the war.