Oona's Blackguard 
Creature — Faerie Rogue
Flying Each other Rogue creature you control enters with an additional +1/+1 counter on it. Whenever a creature you control with a +1/+1 counter on it deals combat damage to a player, that player discards a card.
Legality
standardNOT LEGALpioneerNOT LEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL