Abilities: Vigilance, Intimidate, and "as long as"
I have come across many instances when Vigilance has helped my opponent. With Vigilance your creature can attack when it is your turn, and then remain untap to block while it is still your turn. This is a very useful ability. Armory Guard has a condition on its ability: "as long as you control a gate."
And here is a gate.
I have not made much use of Intimidate, but this may be because I am a new player.