The original cover art for all 12 issues of Watchmen:
Unfortunately I couldn't get any closer than that. They actually had a guard standing watch over these, and velvet ropes to keep fans at a distance.
A Joe Orlando page from Tales From The Crypt #28 (and yes, I'm well aware that it says "The Vault of Horror" - but trust me, it's a Crypt page):
And saving the best for last... Ghastly Graham Ingels' cover for The Haunt of Fear #27:
