One with Nothing

Dimir Signet

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Slither Blade

Dark Ritual

Sudden Substitution

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Exchange control of target noncreature spell and target creature. Then the spell's controller may choose new targets for it.

Counterspell

Dimir Cutpurse

Whenever Dimir Cutpurse deals combat damage to a player, that player discards a card and you draw a card.

Swamp

Avatar of Will

If an opponent has no cards in hand, this spell costs {6} less to cast.
Flying