Although Scooby Doo is one of the cartoons from the 70 s, it's undeniably a hit in the following decades. According to Wikipedia, Scooby Doo started its telecast since 1969 so it's not only a cartoons from the 70s but also in 60's.
The group usually solves the mysterious monster they encounter by unveiling the mask of the enemy which normally are those who are with them in the earlier part of the episode. Scooby and the rest of the gang call themselves as Mystery Inc and regularly drive around in the Mystery Machine van.
Google Doodle featured Scooby Doo as their doodle for this year's Halloween celebration featuring five images cycling around if navigated. Scooby is often associated with Halloween since most of their episodes covered ghosts, monster and other mysterious creatures.
Since Facbook users like you must be searching for Cartoons from the 70s, you may also check my Cartoons from the 90s featuring cartoon characters like Dexter, Gon, Pokemon and San Goku.