Class-specific cards for Rogue, that are considered nearly must-haves:

Blade Flurry (rogue ability, combat hero <4>)
    Ongoing: When your hero deals combat damage with a weapon to an ally, you may have your hero deal that much melee damage to another target hero or ally.
            (lets you do easy non-combat damage to elusives, or anyone else that can't be attacked via normal combat...  also generally doubles the damage you do)