Due to planeswalkers being so great almost all of these will have some Duress targets but the problem is that you don't have good odds on getting a hit, even on turn one, making Duress a bit dodgy
For a simple but deadly upgrade, add Zuran Orb, a zero-mana artifact that lets you sacrifice lands for free
You play strong characters, you banish your opponents' characters, and when you don't see any big threats on their side of the board, you start questing
Kill a utility creature early, kill a commander that took some combat damage in the midgame, or throw it at someone's face and draw three once you get your commander down
Jecht, Reluctant Guardian Tidus dad here is a bit surprising to see in black, but has an acceptable front face, and his back face is highly disruptive to opponents while drawing you cards and giving you one attack with a 7/7 Menace