I have wanted the IG Sanctioned Psykers in metal for a long time. Since the last incarnation of the Grey Knight Codex (back in the flying circus of Matt Ward days), they have had a psychic power that allowed them to shoot a S 3 AP 6 large blast template with a range of 36". The trick was that for each additional Psyker after the first, the Strength increases by 1 and the AP decreases by 1. With 6 Psykers, this means that they can lay down a S 8 AP1 large template even from transports with firing points. At 10 points each, this is devastatingly cost effective.
I have three and need three more.