You never really know when a new Miku fan might make an appearance.

Secret Lair Drop

Chord of Calling

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.

Ravnica Remastered

Convoke
Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.

Explorer Anthology 3

30th Anniversary Play Promos

Magic Online Promos

Double Masters

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Search your library for a creature card with converted mana cost X or less and put it onto the battlefield. Then shuffle your library.

Magic 2015

Ravnica: City of Guilds

Convoke (Each creature you tap while playing this spell reduces its cost by {1} or by one mana of that creature's color.)
Search your library for a creature card with converted mana cost X or less and put it into play. Then shuffle your library.