This is a dredge-engined deck fueled by draw/discard or discard/draw mechanics, letting you keep reusing the best dredge cards to mill yourself every time you discard/draw... simply discard dredge cards in exchange for your dredged back cards, milling yourself as the consequence.  With creatures that tap to do this, and instants that do the same, with a priority on choosing any player (in case we can mill one to death), it's an on-demand game-changer under the right conditions.  That of course relies on Laboratory Maniac, Jace, Wielder of Mysteries, and Thassa's Oracle to try and get the wincon.  Recursion abounds to get those back in hand/play if needed.  And it should be realized that instant spells and tap abilities that force a player to discard and draw can 1) win you the game once your library is empty, 2) force someone to lose (at instant speed, which can be useful) if their library is found to be empty, or 3) fuel the engine of dredge cards being discarded and dredge-drawn, self-milling yourself.  You can't have enough discard/draw options in here!  It would be interesting to streamline the deck down to dredge cards, lands, discard/draw cards, and the three wincons above.  (Discard/draw options are preferred over draw/discard if you regularly find yourself with no cards left [if you have no cards, then discarding before drawing will put cards in hand]; but if you draw a lot of extra cards and keep a rather full hand, then lean on draw/discard options.  Just depends on if you run your deck lean/rich on normal card draw.)

I consider Sidisi, Brood Tyrant and Muldrotha, the Gravetide to be interchangeable commander options, as the deck isn't likely to be built around either one more than the other.  I think Sidisi might be the quicker option, while Muldrotha will let you build a stronger board state, but tie up mana resources in the process, slowing down the dredge engine.

Kozilek, the Great Distortion is kinda fun if you can get it into play and have a way to draw cards at instant speed (like Geier Reach Sanitarium), and have enough dredge options in your grave already.  When your opponent casts a spell with X cost that you want to counter, force yourself to draw a card, then dredge one from your grveyard with the same mana cost, which then gets discarded back into your grave.  This is of course assuming you don't have a discard worthy option in hand with the right cost.  Kozilek isn't cheap, of course, but when he's in play you'll need to be into the game a touch anyway.

Alhammarret's Archive shines in this deck, and we draw tons of card as is, so doubling that only helps get the game over quicker.  Must include.

Blood tokens are great, because the required discard is part of the cost, making the discarded (dredge) card an option to then draw back to your hand using its dredge mechanic.  Any card that has a discard as part of the cost (before the colons) to draw can be used like this.  Similarly, any card that allows you to discard then draw can be used the same.  And again, similarly, any card that makes you draw then discard can be used with dredge cards in your grave... dredge-draw them (and self-mill), then discard them back to your grave to be used again.

Searched:

-draw/discard (tap/instant), all/target player(s)

-dredge

-recursion? flashback, jump-start, disturb, aftermath, escape

-delve

-threshold

Need:

-card draw