First strike (This creature deals combat damage before creatures without first strike.),
trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever Sardian Avenger attacks, it gets +X/+0 until end of turn, where X is the number of artifacts your opponents control.
Whenever an artifact an opponent controls is put into a graveyard from the battlefield, Sardian Avenger deals 1 damage to that player.