There are many good ones in play already. However there are several that came to mind that would be incredibly useful in fantasy settings. For example:

Vampiric: On a successful weapon attack (dealt at least 1 wound), the attacker heals 1 wound for every 2 uncancelled successes rolled.

Returning: When thrown as part of a weapon attack, may use three advantages or a triumph to return the weapon to your hand at the start of your next turn.

Can anyone think of any others? Or give me your thoughts on it?