Flying, haste Whenever an opponent casts their second spell each turn, draw a card. Partner (You can have two commanders if both have partner.)

Flying Whenever an opponent draws a card, you may draw two cards.

Flash Flying Whenever an opponent draws their second card each turn, you draw a card. {3}{U}: Each player draws a card.

Whenever an opponent draws a card, if you control a red permanent, you may have Kederekt Parasite deal 1 damage to that player.

Flash When Orcish Bowmasters enters the battlefield and whenever an opponent draws a card except the first one they draw in each of their draw steps, Orcish Bowmasters deals 1 damage to any target. Then amass Orcs 1.

Meet in Reverse — You draw cards from the bottom of your library rather than the top. Spoilers — Whenever an opponent scries, surveils, or searches their library, put a +1/+1 counter on River Song. Then River Song deals damage to that player equal to its power.

Deathtouch Whenever you draw a card, you gain 2 life. Whenever an opponent draws a card, they lose 2 life.

Flying As Talion, the Kindly Lord enters the battlefield, choose a number between 1 and 10. Whenever an opponent casts a spell with mana value, power, or toughness equal to the chosen number, that player loses 2 life and you draw a card.

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.