I haven’t seen enough of the 1800s to judge, but from what i’ve seen of the first 10 years of the 20th century, these directors stood out best.
Georges Méliès
Méliès basically carried the 1890s on his back and continued to dominate all through the 1900s. His innovative stories with ridiculous plots were deeply missed the following eras.
Segundo de Chomón
More of a poor man’s Méliès but still great. His short films contained the same amount of fantasy and magic that made Méliès so great.
D.W. Griffith
This was only the beginning of Griffith, i’d say that he dominated the dramatic films of the decade while most were still experimenting with fantasy (whose interest sadly decreased the following decade) whilst his films spoke to the audience more I guess.
Edwin S. Porter
Not part of the three greats but certainly worth a mention. He had both drama and fantasy in his films which the top 3 did not.