Lin Sivvi, Defiant Hero is a rare Legendary Creature — Human Rebel card from Secret Lair Countdown (SLC), collector number 2000. Current market price: $1.32 (foil $1.54), TCGplayer market prices via Scryfall.
{X}, {T}: Search your library for a Rebel permanent card with mana value X or less, put it onto the battlefield, then shuffle. {3}: Put target Rebel card from your graveyard on the bottom of your library.