Other members may know this site already - but I've just discovered the most extensive collection of spanking drawings I've yet seen on the net. It's a tumblr site, and the link is
https://otkhaught1.tumblr.com/archive. Each month the person who compiles it posts hundreds, quite possibly thousands of different drawings: M/F, F/M and F/F. (I've yet to spot any M/M.) Some of the artists will be familiar: Paula Meadows, Endart, Wolfietoons, Kami Tora, etc, but there are plenty more.
How far back it goes I don't know; so far I've only explored back to last November....