So you could Dack's Duplicate your own Mulldrifter, draw two cards, swing for three damage over defenses, and now have a 3/3 flyer out that can get bigger and bigger over time
With effects that range from slow, steady sources of damage that drain your opponent 1 life at a time to massive spells that consume half their life at once, theres a life loss card for any strategy
Psionic Ritual Another unique support card for Horrors (and tribal tribal decks with Maskwood Nexus), this is costed after Minds Desire for a reason
I also think these suggestions probably give away the direction I would try to take the deck with my changes: a more efficient, interactive deck that focuses on ramping toward Sauron mana reliably alongside a mix of interaction and reanimated monsters to impact the game in the meantime
I really like this build, and for just $32.65, I hope you will too