By current generation you mean by children born after 2012 right? Because the previous generation was gen Z (which was from around 1997 to 2012). Anyway, it is a little hard to say which cartoon defined this generation. Sure you could say shows like Adventure Time, Regular Show, Gravity Falls and Legend of Korra were, but they were a lot more know by gen Z and gen Y. I'm not sure if many kids born in 2013-onwards watched those shows. And they premiered when it was a Gen Z period. Their best on what defined is what they are being shown and popular with them since at least 2016 (the earliest time that newest generation gets memories). What modern cartoons could define them. We Bare Bears, Loud House and Miraculous Ladybug. I can even throw Teen Titans Go, Amazing World of Gumball (this premiered in 2011, but virtually all of CN feeds are airing it like crazy along with TTG, so they clearly must be big with today's kids) and perhaps Steven Universe there. For preschoolers it would be Paw Patrol.