Right off the bat, Narset is a notoriously difficult commander to deal with, having both hexproof, so your opponent can't target her, and first strike, making her more resilient in combat
It works best with cheap creatures that have evasion and/or strong enters effects, like Baleful Strix and Spyglass Siren
The defaults work great, but if you're plowing through a stack of slabbed PSAs and want to squeeze out the last bit of precision, lock it to slabs
If Chaos Orb turns over completely at least once during the flip, and lands resting on the chosen permanent, destroy that permanent
Not to mention the indestructibility and the devotion part
5) White Aggro Deck: This is an insanely aggressive creature deck