Probably the most widely known quest image is this 1955 drawing by Pablo Picasso.
Reading the entry in Wikipedia reminded me that Sancho Panza’s donkey was Dample.
The Knight at the Crossroads by Viktor Vasnetov, 1878
Don Quixote and Sancho Panza, by Honoré Daumier, 1868
The Alaska Advocate’s media empire, by Bud Root, 1976