Deathmark

In Commander, Deathmark is a meta-read card: in a pod heavy with green and white — which describes most pods — it punches above its cost by a wide margin, handling threats that black otherwise needs three or four mana to answer. In Legacy and Vintage, the conditional clause is a liability against blue-black or red-based strategies, so it sees sideboard-only play targeting Tarmogoyf and friends. Modern and Pioneer treat it the same way — pure sideboard hate against white-green aggro and midrange shells, where it earns its slot by killing a Noble Hierarch or Collected Company target on the cheap. In Commander it's the closest thing to a free slot: if at least two opponents reliably run green or white, Deathmark belongs in the 99.