While the simple One-Step, and then the Foxtrot (same dance, new name) dominated the dance floor, there were dancers who heard the wild syncopations of that Ragtime and then Jazz music, and just had to kick up their heels, and they were doing so before the Charleston arrived on the scene.
This page is devoted to the "root" dances that preceded the Charleston. So far, I've found good film documentation for two: The Texas Tommy, from around 1911 in the black community and the Shimmy, from around 1920 in the white community.
Texas Tommy
The name "Texas Tommy" is often affixed to this particular style of dancing, though it's hard to know, if you asked the people in this film what they were doing, what they would tell you.
The main interest in this is that it shows that the dances of the following decades did not spring fully formed from nothing. Many of the elements of later dances can be seen and clear lines of evolution and influence will be clear as this project continues.