The 1e Dungeon Masters Guide is still one of my favorite RPG books — maybe because when I began playing it was off-limits to players. You can supplement all the older versions of D&D with it pretty decently, and it fills in the gaps for retro-clones have too. Anyway one of the many things that were unique to it were the cartoons by Will McLean (not to be confused with the folk song writer). They weren’t all great but mostly they hold up. (I always thought there should be more cartoons in the Players Handbook, too.)
On a lark I looked him up online and I see he’s involved in the Society for Creative Anachronism, big surprise. He also wrote a book on England in Chaucer’s time, and was involved with various SCA publications.
Mr. McLean has a Deviant Art gallery here, which is worth checking out, though it does not have his old DMG and Dragon Magazine toons.
Swords & Dorkery 
The DMG is gold..pure and simple..we still use it and we are playing BRP/Classic Fantasy.
Thanks for this, Mike!—Will’s contributions have always stood out to me as well, and I’m happy to see that he’s still creating art 😀
Allan.
My favourite of his DMG cartoons is the one with the party getting ready to infiltrate a ratmen lair – with stuck on fake mouse ears and noses! The fighter threatens the wizard “this had better work!” lol!
Sadly- Will McLean passed away at the age of 58 in 2015. I read his Obit and saw that he did AD&D cartoons/art- I was a fan of his without knowing it.
Will was the heir of a large newspaper fortune (when that was a thing). He lived an interesting/great life. He filled his life with art, history, philanthropy and family. I’m sure he will be missed.
https://www.legacy.com/amp/obituaries/tributes/176242034