Many of the Arbuckle/Keaton films exist.

Most of Arbuckle's silent films became lost due to the poor quality of the film preservation back then. However, there are a several silent shorts from the 1910s that exist. Three of my favorites are listed in Amazon Video On Demand which include 'Fatty's Spooning Days' (aka: Mabel, Fatty and the Law) from 1915 and 'Fatty Joins the Force' from 1913, as well as 'Fatty's Suitless Day' from 1914. The picture quality is grainy with some scratches here and there, but they are worth a look.

Well, it'd be hard to say for sure as there are probably (and hopefully) more titles hidden somewhere deep down in film archives around the world. However, according to IMDb, he appeared in 163 films as an actor (the number is probably not entirely accurate, as he may have appeared in a few very early films in uncredited roles). At least 75 or so of these survive in some form, though some in better shape than others, of course. I bet there are even more, including the ones not available for public viewing at the moment. Also, remember that Roscoe directed several films under another name after the scandal, and some of these still exist as well.

Thanks for your reply. So, ballpark numbers, what percentage of the films he made do you think are known to have survived?

Happily, quite a few of Arbuckle's films are currently available to the general public. Several titles dating back from 1914-16 (and then some later ones as well) were included, restored and remastered, in the DVD collection "The Forgotten Films of Roscoe 'Fatty' Arbuckle" from Laughsmith Eintertainment/Image in 2005, and his twelve (I think?) surviving films with Buster Keaton from 1917-19 have made it to DVD as well. Reportedly, a new DVD-set of Arbuckle-titles is currently in production. So while most of Arbuckle's original film prints may have been destroyed, copies of his films have continued to turn up to the present day.