I finished my play set of Baleful Strix this weekend and thought how I wished it were legal in Modern.
It got me thinking though being a sweet UB costed creature, flying and deathtouch, 1/1 and has card draw when it comes into the battlefield. What makes this a great creature for those colors? Obviously the card draw but it's also a great blocker with the flying and deathtouch.
Perhaps a UB mechanic that buffs the creatures power but also enables some card draw. Like maybe you get card draw when it enters the battlefield, but it also puts a +1/+1 counter on the creature for every card drawn until end of turn.
Think of a combination of Baleful Strix and Glaze Fiend (but not artifacts causing the buff, actual card draw).