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.

Basking Rootwalla

{1}{G}: This creature gets +2/+2 until end of turn. Activate only once each turn.
Madness {0} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Roar of the Wurm

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.)

Deep Analysis

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.)

Merfolk Looter

Krosan Reclamation

Target player shuffles up to two target cards from their graveyard into their library.
Flashback {1}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Wonder

Flying
As long as this card is in your graveyard and you control an Island, creatures you control have flying.

Centaur Garden

{T}: Add {G}. This land deals 1 damage to you.
Threshold — {G}, {T}, Sacrifice this land: Target creature gets +3/+3 until end of turn. Activate only if seven or more cards are in your graveyard.

Unsummon

Return target creature to its owner's hand.

Naturalize

Aquamoeba

Discard a card: Switch this creature's power and toughness until end of turn.

Island

Waterfront Bouncer

{U}, {T}, Discard a card: Return target creature to its owner's hand.

Circular Logic

Counter target spell unless its controller pays {1} for each card in your graveyard.
Madness {U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Ray of Revelation

Destroy target enchantment.
Flashback {G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Arrogant Wurm

Trample
Madness {2}{G} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Careful Study

Forest

Wild Mongrel

Discard a card: This creature gets +1/+1 and becomes the color of your choice until end of turn.

Flash of Insight

Look at the top X cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.
Flashback—{1}{U}, Exile X blue cards from your graveyard. (You may cast this card from your graveyard for its flashback cost, then exile it. You can't exile Flash of Insight to pay for its own flashback cost.)

Compost

Whenever a black card is put into an opponent's graveyard from anywhere, you may draw a card.