Family's Favor

Whenever you attack, put a shield counter on target attacking creature. Until end of turn, it gains "Whenever this creature deals combat damage to a player, remove a shield counter from it. If you do, draw a card." (If a creature with a shield counter on it would be dealt damage or destroyed, remove a shield counter from it instead.)

Maelstrom Nexus

The first spell you cast each turn has cascade. (When you cast your first spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)

Telekinetic Sliver

All Slivers have "{T}: Tap target permanent."

Leeching Sliver

Whenever a Sliver you control attacks, defending player loses 1 life.

Synchronous Sliver

Root Sliver

This spell can't be countered.
Sliver spells can't be countered.

First Sliver's Chosen

Sliver creatures you control have exalted. (Whenever a creature you control attacks alone, it gets +1/+1 until end of turn for each instance of exalted among permanents you control.)

Toxin Sliver

Whenever a Sliver deals combat damage to a creature, destroy that creature. It can't be regenerated.

Vampiric Sliver

All Sliver creatures have "Whenever a creature dealt damage by this creature this turn dies, put a +1/+1 counter on this creature."