The original Scooby Doo show aired from 1969-1971 and was a product of its time. We've seen reboots, remakes, and special episodes in every decade since it first aired. London-based artist Julia Wytrazek imagined the main characters in the popular styles of every decade of the Twentieth Century. You can see all of the images here. I especially like the 90s reference to Buffy the Vampire Slayer.
Bonus item: if Hunter S. Thompson wrote an episode of Scooby Doo.