Edgar, King of Figaro is a free win and a must include
According to EDHREC, the most common strategy used in Grixis decks is wheel: spells that make you and your opponent discard your entire hands and draw new ones, or at least a certain number of cards
It can also regenerate itself or give itself haste, making it an effective way to deal large amounts of poison damage
It is quite cheap at only three mana, and the second ability may save your game in the most complicated moments
Stiltzkin, Moogle Merchant From a pure power level, Stiltzkin probably should be even lower, but the moogle merchant is an interesting donating card that could open up some fun play for people, and isnt something we see too much of
White Star Charter While Star Charter isnt the broadest card draw spell, this little bat fits perfectly in lifegain stratigies