Quiet Speculation

Search target player's library for up to three cards with flashback and put them into that player's graveyard. Then the player shuffles.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Flashback costs you pay cost {2} less.
Flashback costs your opponents pay cost {2} more.

Sacrifice Seal of Cleansing: Destroy target artifact or enchantment.

Create a 4/4 green Beast creature token.
Flashback {2}{G}{G}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Create a 6/6 green Wurm creature token.
Flashback {3}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Enchant creature
Enchanted creature can't attack.
Threshold — Enchanted creature can't block as long as seven or more cards are in your graveyard.

Exile target creature. Its controller gains life equal to its power.

{T}: Add {C}.
{T}: Add {G} or {U}. Yavimaya Coast deals 1 damage to you.

{T}, Pay 1 life, Sacrifice Windswept Heath: Search your library for a Forest or Plains card, put it onto the battlefield, then shuffle.

Create a 3/3 green Elephant creature token.
Flashback {3}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Target player draws two cards.
Flashback—{1}{U}, Pay 3 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.