Like its old Alpha companion Lightning Bolt, Counterspell has stood the test of time as an efficient, flexible piece of interaction
But he also lets you exile an equipment, instant, or sorcery card from your graveyard and play it and he deals direct damage to any target whenever you cast a noncreature spell
Ramp Spells and Mana Rocks Non-creature ramp is usually a bit slower than mana dorks, but its way more reliable
Change 3 to 5 cards max per iteration, then test again
Pre-Eldrazi, we've almost never seen Crack in Modern, barring a Gerry Thompson feature on StarCityGames of Kanaoka Yoshihikos Mardu Pox deck
Either option scales up in multiplayer