Hibernation's End

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever you pay Hibernation's End's cumulative upkeep, you may search your library for a creature card with mana value equal to the number of age counters on Hibernation's End, put it onto the battlefield, then shuffle.

Prime Speaker Vannifar

{T}, Sacrifice another creature: Search your library for a creature card with mana value equal to 1 plus the sacrificed creature's mana value, put that card onto the battlefield, then shuffle. Activate only as a sorcery.

Yisan, the Wanderer Bard

{2}{G}, {T}, Put a verse counter on Yisan, the Wanderer Bard: Search your library for a creature card with mana value equal to the number of verse counters on Yisan, put it onto the battlefield, then shuffle.

Pyre of Heroes

{2}, {T}, Sacrifice a creature: Search your library for a creature card that shares a creature type with the sacrificed creature and has mana value equal to 1 plus that creature's mana value. Put that card onto the battlefield, then shuffle. Activate only as a sorcery.