This is my quick take on a mill deck, with a tribal aspect and a hint of control to assure you're hardly touched by things you don't want to be affected by as the deck wielder denies the usage of cards key to the opponent. Here is a quick layout of the deck:
Spells and Enchantments:
The cheapest of these cards is Extirpate to eliminate pesky cards via opponents graveyard as they fall into the grave through various cards in this deck. Some of these being spells like Glimpse the Unthinkable, Mind Funeral, and Traumatize. Some counters featured are Countersquall as a beefed up Negate and Psychic Strike as a fitting Cancel that mills the opponent a little. I decided on Distress over Thoughtseize to avoid the 1 life loss. The only Enchantment in here is Deadbridge Chant to work as a secondary draw and add some cards in the grave to power two cards in here.
Horrors:
I decided on Horrors as I saw that the effects on some of them work within the goals of the deck, so Cavern of Souls ensures they cannot be countered by fellow blue mages. First one is Thing in the Ice
as a decent defender that eventually disrupts the board, in this case only on the opponents side. Phyrexian Obliterator is a menacing creature that harms as it blocks, wiping the slate clean in combat. Four of the others are all 5 CMC and limited to one; these are: Consuming Aberration (milling out the opponent and getting power from it), Lord of Extinction (power gained from both graves to add more power swings), Nemesis of Reason (more mill and great defender), and The Gitrog Monster (adding land and card draw through a self destructive mean). The last Horror included is a Mindleech Mass that steals a card from the opponents hand with each successful attack (perhaps more possible thanks to Thing in the Ice, Phyrexian Oblitirator, and countless spells and abilities).
The final aspect in this deck are the 8 planeswalkers (2 different Jaces, Liliana, and Vraska). Jace, Vryn's Prodigy
helps early as a good way to shape a hand before trasforming to a planeswalker that can weaken the enemy attack, Flashback spells, and ultimately mill the opponent some more as Jace, Telepath Unbound. The other Jace, Jace, Memory Adept is the perfect mill planeswalker through each ability of his. Liliana Vess helps limit the opponent's options, tutor a card, and possibly add an undead arsenal under your control late game. Finally, Vraska the Unseen cloaks herself in the shadows from damage before destroying annoying cards on the field and later enlisting assassins to kill the game once the coast is clear.
Honorable Mention:
To help out the mana color curve being overwhelmingly black (with a side of blue and a splash of green) Urborg, Tomb of Yawgmoth is included to make sure there are always enough swamps and black mana to play spells (especially the mono black Oblitirator needing 4 black mana to cast).
