There is nothing that is anywhere close to comprehensive for the US.
As a start:
http://www.stampsmarter.com/feature...rn_Home.htmlThere is also an out-of-print book
Start of USPD/USPS pictorial handcancels by the Pictorial Eleven, covering the 1940s to early 1980s. That is a defunct collector group that specialized in US pictorial cancels. The books might be a collection of the xeroxed pages of newly found cancels sent to members monthly.
New ones are announced in the USPS
Postal Bulletin and there is an archive that goes back to 2001, but even that is not comprehensive for the time period.
My estimate is that there are over 50,000 US pictorials and fancy cancels including machine flags and machine cancels.* That number is for different ones by design and city/town. There are further different colors, different dates including reuse every year, and minor varieties.
Countries that issue/have issued a lot of pictorials aside from FDC cancels include Germany, Great Britain and Japan. There may be book references for those. As new ones from any country come out all the time, finding ones for (say) a specific topic is pretty hit-or-miss. You have to enjoy the thrill of the hunt through online stores and dollar boxes.
Is there something specific you are looking for?
*EDIT: My guess for fancy and pictorials from about the 1890s to date.