Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.
"It's a dangerous business, Frodo, going out of your door. You step into the Road, and if you don't keep your feet, there is no knowing where you might be swept off to."
—Bilbo
Farseek can find any land with any of the listed land types, including nonbasic ones, even if that land is a Forest in addition to one or more of those types.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.