Check out Kill Their Library for more card ideas, and I would definitely suggest some cards with high toughness and to throw in Phenax, God of Deception.

@mnfishwerman7
Thank you for the comment. Phenax is a good card and I will see what I can do to add it in.
That is a sick looking commander deck btw.

mnfishwerman7 & Ninjew42 - Feel free to check out my mill deck Drawing Dead. It ranked #1 in a couple of different categories a week ago. I'd also like to hear your thoughts on how it could be improved.

Sculpter"s Codex is a sick Mono blue mill I got a few ideas from. Check it out and upvote it.

No Millstone? :-D

No, no Millstone. I do love it and thought about putting it in, but it is too slow.

Do you find Traumatize and Jace, Memory Adept to be too slow? I haven't tested this deck, obviously, but 5 mana seems like a lot in a deck with 21 lands. I would want to run 2 more lands and another Breaking / Entering.

Also, have you considered adding a white splash for Kaya, Orzhov Usurper in the sideboard? She can help keep you alive against aggro and burn.

Epidilius, I don't usually have any mana issues and because Jace is a 1 off and Traumatize is not the focus of the main combo, just an "Oh, I win Now. GG." kind of card, I don't worry about the 5 CMC of those cards. I like to give people a chance but still have that ability to crush them in a single blow. Its more fun that way IMO.

Startled Awake  ^Flip would be a solid addition to the deck, maybe 2x? It has a very curious effect when it is with multiple copies of Fraying Sanity-- the effect stacks! Thus, 2x Fraying Sanity in place, play Startled Awake  ^Flip. Result, 13 cards in the graveyard from Startled Awake  ^Flip, then the first Fraying Sanity triggers for 13 more cards, then the second Fraying Sanity triggers for 26 additional cards into the graveyard-- 52 cards into the graveyard! You'd definitely want to go to about 23 or 24 lands, though, if you decided to do that.

BioProfDude, I though about putting in Startled but found that 2x breaking does more dmg to the Library with 2x fraying on the field. 16 > 16 > 32 for 64 milled. To be fair, if I get 2x fraying on them they are pretty much toast any way.

Nice deck. This may not at all be what you want to do with the deck, but Duskmantle Guildmage can be a very effective way of winning, often draining the opponent out in one turn when Fraying Sanity is on the field. Again, not sure if this is what you’d want for the deck, you seem more focused on pure mill plan so this might not fit, just maybe something to consider.

BRG24, that is an interesting idea for another possible win con. I would need to have roughly 6 lands out to make that work but it is doable. Thanks for the idea!

I'll share my experience with you. I tried a competitive UB mill in Pioneer for a while, but it was far too slow. There are not many great mill cards in Pioneer. So, I changed my build to combo-based with 4 Fraying Sanity and 4 Traumatize. And it started to work.

It made a great difference and I started to win. I play now Thoughtseizes, Bontu's Last Reckonings, sideboard Leyline of the Void, Fatal Push...

I think you oughta try and see for yourself. Because, let's be frank Mind Sculpt is pretty meh. And the 0/4 creatures to stop aggro don't always do the job. The only real good card is Thief of Sanity and even him is too vulnerable. The opponent won't waste removal on a wall if he can wait to target the Thief.

My best bet is that the best version of this deck is focused on combo and a possible alternate wincon with a planeswalker or a manland. Think of all the slots you'll free if you abandon the non-combo mill cards and how much you'll gain by adding cards like Cry of the Carnarium, Languish, etc.

Yuri200X, I would love to include Bontu's Last Reckoning in the side board as it is a better board wipe IMO than Cry of the Carnarium, sadly I do not own any.

While I fully understand (and agree) that Thief of Sanity is super strong, I do agree with a few others that it is relatively vulnerable... is Ashiok, Nightmare Weaver a better option? In the very least, she has an immediate effect once she hits to guarantee 3 cards in exile, and when your opponent works on removing her you're either saving yourself life points, or, they're using the same resource to kill her as they would the Thief.

I know you said it isn't meant to be a controlling deck, but functionally, the two cards are very similar... one just has more toughness (unless they have exactly Dreadbore).

Squirrelbacon, Thief is super vulnerable and an immediate target as soon as it hits the board, and will get killed asap by all opponents because of the threat it implies. But that's ok, that is his job. Ashiok is in the sideboard as her effect stops the effectiveness of Drown in the Loch, one of my primary kill/counters. I really want to add Narset, but sadly I own none.