Sidisi Brings all the boys from the 'yard (EDH / Commander)

Self Mill + Mass Reanimation

Instant wins are mikaeus + triskelion(easily achieved by double reanimation spells like victimize)
or milling your entire library and lab maniac or sacing your entire board with multiple blood artists effects in play.

Mirror mad phantasm in your graveyard and necrotic ooze or body double in play and 1U dumps your whole library into your graveyard. Then you can usually dread return a lab maniac and draw the win.

Also secret tech is Songs of the damned usually dark ritual that adds 5-40 mono seems decent right? Splendid reclamation does decent work too 4 mana adding 10+ lands in play.

The deck runs a few budget sweepers and a pile of ways too bring things back from your graveyard to hand, rebuy mass reanimate, wraths and combo pieces.

The deck was originally built around Sins Of the past which is a worse version of spell twine... so I run both, ideal target is Rise from the dark realms but any mass reanimate is usually good enough. If your whole library isn't in your yard yet the return of all the creatures should eternal witness effect to get a bunch of cards back into your hand.

The deck doesn't run a ton of tutors but it can find the pieces you need with relative ease. Dimir house Guard finds splendid reclamation, birthing pod, necrotic ooze.

Birthing pod (or eldrich evolution) turns 3 drops into ooze and 4 drops (including Sidisi into mirror-mad) which should be your first target generally. There is something that returns cards from yard to hand at 3/4/5/6 so you can get something you need back easy.

There are a few cards missing that might make this deck better (living death/ living end ect.) and the manabase could be upgraded but it's really a blast