I’m not an expert but from my acknowledge these are the biggest hits by 3rd generation groups in Korea:
-EXO: Growl (2013)
-BTS: Spring Day (2017)
-TWICE: Cheer up (2016)
-BLACKPINK: DDU-DU DDU-DU (2018)
-Red Velvet: Red Flavor (2017)
-IKON: LOVE SCENARIO (2018)
-Winner: Really Really (2017)
-WANNA ONE: Energetic (2017)
About other groups I genuinely have no idea, if some wants to add other groups go ahead I’m curious as well.