That delay buys you time to swing or stabilize, making it especially nasty against token swarms
Mari, the Killing Quill is easy to cast, and with deathtouch, your opponents will be less likely to block your Assassins out of fear of losing their own important creatures
Here is the exact protocol to find a card's true market value: Filter by "Completed & Sold" Items: When searching for your card on eBay, scroll down the left-hand filter sidebar and check the boxes for Completed Items and Sold Items
Demonic Tutor can seek out powerhouse cards on demand, like Tyvar Kell and Shaman of the Pack.
Neo Upper Energy is pretty strong, and far less restrictive than the thematically similar Reversal Energy
The Serpent Society Five poison counters is quite the ward cost, yet it isnt even the scariest part of The Serpent Society: A cheap Grave Pact in the command zone should terrifying anybody with a creature-focused strategy