The nebulous nature of iconic makes this tough.
Bojack is a masterpiece, but unfortunately the adult animation industry doesn't seem to care and is still mostly churning out crap.
If influence and setting the trend is the main factor, I think Steven Universe is probably the most noteable cartoon for the current landscape, and before that it was Adventure Time.
https://twitter.com/OocWTC/status/1348011667976699904?s=19