The Drifter
Some person.
I would dare to say SpongeBob is more popular than almost every cartoon today. Simply because of international viewership, ten millions of people from various countries watched SpongeBob at some point. Cartoons like Adventure Time or Gravity Falls, although popular in the US barely makes it to the international stage. Other contender would be those old Disney/Looney Toons/Tom & Jerry cartoons from the 30s-50s, because of how they're syndicated, those cartoons probably are still aired in many different stations around the world until today. Also I excludes Animes.