You say you're going for more sacrifice than discard but the current list feels very much the opposite to me. If you are serious about wanting to make the deck more casual friendly, cutting all of the cards that exclusively care about discard does seem like the easy way to get down to 100. Having cards that do both like Rankle's Prank will probably be more palatable, even if the outcome is actually even more lopsided. As an aside in the event you do keep some discard spells, you'll be better off paying a little extra for the multiplayer focused options like Delirium Skeins vs. something targeted like Duress. Obviously, if you want to do a lot of 1v1, that evaluation changes. I like the idea of focusing on a sacrifice shell with all of Grave Pact, Dictate of Erebos, and Butcher of Malakir to ding opponents while you're sac looping your own creatures with various reanimator tools. Cards like Hell's Caretaker or Whisper, Blood Liturgist are favorites of mine since you can easily convert your chumps into discarded bombs or re-trigger ETB and death triggers. You have a ton of cheap Fleshbag Marauder-type cards and that's the real reason I'd recommend this angle. If you stick with at least some of the discard package, you can run plenty of Burglar Rat and Virus Beetle 1/1s to take advantage of Shirei, Shizo's Caretaker which is also conveniently good with Valgavoth's Faithful and other potential synergy pieces like Viscera Seer, Blood Artist or Zulaport Cutthroat.

I'll also list some other cards I'd consider cutting, regardless of the focus on discard or sacrifice. Crypt Ghast feels excessive here since by the time you can play it and untap on the following turn, there's currently only two cards that you wouldn't be able to cast anyway. Since I'm also recommending the cut of All is Dust anyway for being too symmetrical of a wipe for its high cost, I don't know that you'll need all that mana very often. The obvious counterpoint here are the x spells, but I'd urge caution on keeping too many of those too. Unless you're ending the game with a final enormous Torment of Hailfire, these types of effects can fall squarely under the "feels bad" category, or at least that's my experience. If you do want to keep them as wincons, you probably want even more cards like Ghast to improve consistency in reaching that goal. For somewhat similar reasons, I'd also consider cutting Dark Ritual and Culling the Weak. Turbo-ing out your oppressive commander is exactly the kind of play pattern that earned the recent commander bans their new status. If the other players at the table feel like they have time to prepare potential answers to Tergrid, I think people will be much happier to play with you. And if you feel you need more mana and a way to sac guys you want in the yard, Ashnod's Altar and Phyrexian Altar are always an option. In terms of draw, I like engines that play off your deck's existing themes like Waste Not, Geth's Grimoire, Grim Haruspex, Harvester of Souls, etc. as opposed to once a turn effects like Dark Confidant or Phyrexian Arena. They may not always be more efficient but they're certainly more interesting. Necrodominance is an option I'd be careful with though since it has some anti-synergy with self-reanimator strategies. I like the idea of Deathgreeter to recoup some of the life loss from symmetrical pox effects and to benefit from mass sacrifice. I just think some of the previously mentioned options at two mana do the job better. Similarly, I feel that Osseous Sticktwister will accomplish less than some similar cards in the deck since your opponents are free to choose the life loss in a format that offers them plenty of life to spare. If you were going for a more explicit life drain strategy, I think the card could pair nicely with other 8rack staples. Unstoppable Slasher is another card that is only good if you're focused on dropping life totals quickly, and with no obvious ways to guarantee the damage gets through, I don't see this guy as being too impactful. The final card I'll mention is Mithril Coat. It makes sense on paper to protect your commander when you know it's going to get targeted. However, Tergrid is so feared at many tables that she's likely to get targeted and removed before you even have the spare mana to equip her. For this reason, I'd prioritize cheaper protection like Boots/Greaves. You could even try one of the many instants and auras that offer a one-time reanimation effect since those will also protect against your own sacrifice effects where equipment will not.