mtg opponent draws a card Top 10 Draw Triggers Does opponent choose to draw

Efficiency can be determined simply by the reward you receive at certain mana costs (Counterspell and Cancel do the same thing, but Counterspell costs less), the total payoff you receive from a single card (Hull Breach and Decimate are both good cards, but Decimate usually covers much more ground), or the payoff you receive in conjunction with other cards (Anointed Procession makes other token production cards completely absurd if unchecked, which is usually better than adding one more card that simply makes tokens like Spectral Procession in a token strategy)

One premium foil token from Theros Beyond Death

Verify the black core within the card stock Need Certainty

Because of this, Lingering Souls was banned less than two months after its release