In this article, Ill highlight my top 10 cards from Duskmourn
In particular, the third mode is what truly sets this card apart from others on this list, as stealing an opponents permanent usually costs more than three mana
Vampiric Tutor Any card for one mana and at instant speed
You can still cherry-pick some of the sweet choices, like Bloodbond Vampire or Cordial Vampire, which might get you into some interesting loops
Id only avoid this if I had a fairly low curve and just wanted to attack with cheap creatures, as its ultimately just another mana source if the game goes long enough
Another is to play some number of enchantment creatures and hope your opponent has a creature you can swap with Daring Thief first, hopefully one that wont be too big to attack into, like say Nyx-Fleece Ram