Anthem Achilles Davenport Freerunning (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.) Menace (This creature can't be blocked except by two or more creatures.) Other Assassins you control get +1/+1
Most cards on this list let you double +1/+1 counters, like Kalonian Hydra, since theyre the most common kind, while others let you double any type of counter
Points for fun and novelty, though
Murders at Karlov Manor Collector Boosters are brimming with potential alternate art between the case files, magnified, and Ravnica City showcase treatments
So while Counterspell might be able to deal with any threat, most times you'd be better off drafting Dark Banishing or Incinerate so you could drop early creatures, and then use the removal to mop up afterwards instead of having to wait for your gracious opponent to walk into your untapped Islands
Dance of the Skywise: Battle trick for a critter in trouble