Nihilister, in World Ender

Whenever a player sacrifices a non-token permanent, deal 1 damage to each creature and planeswalker target opponent controls.

{t}: pay 3 life and sacrifice a creature and make a 4/4 artifact creature with reach and menace

Nihilister, in World Ender gets +1/+1 for every artifact creature under your control

Heretic squad - (heretic squad creatures change there coloured mana cost to your commanders if your commander is a heretic squad creature)