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.)

Wonder

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

Impulse

Look at the top four cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Psychatog

Discard a card: This creature gets +1/+1 until end of turn.
Exile two cards from your graveyard: This creature gets +1/+1 until end of turn.

Gush

You may return two Islands you control to their owner's hand rather than pay this spell's mana cost.
Draw two cards.

Cephalid Coliseum

{T}: Add {U}. This land deals 1 damage to you.
Threshold — {U}, {T}, Sacrifice this land: Target player draws three cards, then discards three cards. Activate only if there are seven or more cards in your graveyard.

Accumulated Knowledge

Draw a card, then draw cards equal to the number of cards named Accumulated Knowledge in all graveyards.

Island

Polluted Delta

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Smother

Destroy target creature with mana value 3 or less. It can't be regenerated.

Counterspell

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Underground River

{T}: Add {C}.
{T}: Add {U} or {B}. This land deals 1 damage to you.

Swamp

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Powder Keg

At the beginning of your upkeep, you may put a fuse counter on this artifact.
{T}, Sacrifice this artifact: Destroy each artifact and creature with mana value equal to the number of fuse counters on this artifact.

Foil

You may discard an Island card and another card rather than pay this spell's mana cost.
Counter target spell.

Portent

Look at the top three cards of target player's library, then put them back in any order. You may have that player shuffle.
Draw a card at the beginning of the next turn's upkeep.