I played multiple formats for months with Skullclamp legal, and it was one of the darkest times in Magics history
Drana and Linvala Drana and Linvala can shut down entire decks
accidentally wiping out your board with poorly planned -1/-1 counters is never a path to success
This next step adds the additional rules of the full trading card game, in a format that's accessible for new and returning players alike.
Then each creature that isn't an Insect, Rat, Spider, or Squirrel gets -1/-1 until end of turn for each creature you control that's an Insect, Rat, Spider, or Squirrel
Ixalan (2017) has four new ways to draw cards, three of which are again new versions of old themes, none of which we see that much in the larger picture