Helix is nasty either in decks that apply pressure to race Burn, or in decks that try to stabilize until bigger threats hit the battlefield
Despite other Sliver lords being more powerful, Sliver Queen being the first as well as boasting truly incredible art from legendary Magic illustrator Ron Spencer means that this card will always be a hot commodity
Glass-Cast Heart AND Arterial Alchemy Blood matters a lot in this set
Significantly worse, but having a 4-mana artifact in play on turn 1 has gotten people excited about Metalwork Colossus again
Fishbone Quills and Sleepys Flutes are usually a lovely target to get rid of with some targeted item removal but with a brand new suite of deadly items to come up against like the Lucky Dime, the Sumerian Talisman or the Vault Door and its time to take item banishment even more seriously
You should already be looking for the walking moxes that are green's mana creatures, so supplement them with artifact mana and a range of efficient, beefy green creatures at all points on the mana curve