Mirri, Weatherlight Duelist

First strike
Whenever Mirri attacks, each opponent can't block with more than one creature this combat.
As long as Mirri is tapped, no more than one creature can attack you each combat.

Kardur, Doomscourge

When Kardur enters, until your next turn, creatures your opponents control attack each combat if able and attack a player other than you if able.
Whenever an attacking creature dies, each opponent loses 1 life and you gain 1 life.

Chromium, the Mutable

Flash
This spell can't be countered.
Flying
Discard a card: Until end of turn, Chromium becomes a Human with base power and toughness 1/1, loses all abilities, and gains hexproof. It can't be blocked this turn.