Here's the last of The World Encyclopedia of Cartoons, the 1980 book I got these from. I'm sure I missed some (that are scannable), so I'll probably go back to it at some later date.
Hilda Terry's feature Teena
Still from Duṥan Vukotić's Concerto for Sub-Machine Gun
Werner Wejp-Olsen (WOW)
Adolphe Willette, 1903
Artist unknown, it was between the W and Y sections. Is it supposed to represent the letter X or is it just a nice drawing?
The Yarns of Captain Fibb, for Judge in 1909
Bill Yates, for Saturday Evening Post
There was a syndicated strip of Yogi Bear in the early '60s.
Pino Zacarria (“Zac”)'s Kirie and Leison.
Heinrich Zille for Simplicissimus