Bad River

Sacrifice it for an Island or Swamp, shuffle, and accept that you spent a turn doing it: this is the fetch land template in its first, slower form. The structure that mattered is already present, which is why this plays as an ancestor of the modern fetch rather than a sibling. It enters tapped and dies to its own ability, so the deckbuilder pays a full tempo tax up front in exchange for thinning a land out of the library and arriving on the right two colors. The search clause is wider than the name suggests: "Island or Swamp card" reaches any land carrying those subtypes, so a typed dual answers the call exactly the way a basic does. The real difference from the Onslaught fetches that succeeded it is not what they find but how they arrive. Polluted Delta and its siblings kept the same typed search but entered untapped and asked for a point of life instead of a turn of tempo. That single substitution (life for time) is what turned the template into a manabase keystone, because an untapped fetch can hold up answers or curve out the way a tapped one never could. The Mirage cycle established the shape; the Onslaught cycle that followed only adjusted the price, and the adjustment turned out to be everything.