So, I really like the idea of
The Scarab God in the command zone. He's nasty, and having a way to reduce commander tax is crazy good.
Full disclosure, if you're looking to make the nastiest and meanest SG deck possible, I don't necessarily think tribal zombies is the absolute best way to do it. I would go for a nasty Dimir control shell myself. Nonetheless I can still see some things in here that I can feed back on.
Here's what I see as some of the weaker things in the list:
Value creatures
Gisa and Geralf - I've run these guys at the helm before, and they're in a weird place for zombie tribal. Their ability just isn't enough to generate value from the options that zombie tribal gives you. If you want this ability, I would recommend
Liliana, Untouched by Death instead.
Havengul Lich - This guy
can be really good, but he costs a crap ton of mana to make use of. I personally don't have a place for him in my Varina list, but I do run a pretty lean mana package. If you find yourself with a surfeit of resources and he fits your meta, by all means run him.
Gempalm Polluter - Honestly, it's just really hard to make this guy decent. Cycling him, sure, but how do you repeat that effect? Reanimation won't do it, you need him back in hand, and that means running cards to do it that are probably substandard or just don't work with anything else you're doing.
Token Makers
Dread Summons - Again, if you run enough to make a lot of mana regularly, this could do well, but I think there's better ways to spend your hard earned coin, especially when you're running finishers like
Exsanguinate and
Torment of Hailfire.
Liliana, Dreadhorde General - Don't get me wrong, she's crazy good. But one zombie once a turn isn't stunning, if that's why she's here. If it's the ultimate you're really after that's fine, but you don't have a lot of synergy to help tick her up either, and she isn't cheap to cast.
Army of the Damned - I'm a little biased, I think this is a trap card. It's a lot of mana to shell out for tapped 2/2 tokens even if there's a lot of them.
Endless Ranks of the Dead - This one is super tempting in zombie tribal. I'm of the opinion personally that it's a trap. It's very slow, and very conditional. If you have one or two zombies, it's not worth casting, and if you have a horde, well, you already had a horde, so what does it add? Plus, you have to wait a turn for it to do anything and pray it doesn't bite removal. If it does, you've spent
2bb for nothing. For what it's worth I also think
Rooftop Storm is in the same category.
Tutors
Corpse Harvester - This guy is pretty slow. Swamp tutelage is nice, but be aware that he is slow and expensive.
In terms of what you could add, here's where I've found value in a zombie shell before:
Graveborn Muse - Honestly, in a zombie shell it's a much, much improved
Phyrexian Arena, and Arena is still pretty damn good.
Bone Miser - This guy, frankly, is just bonkers. You don't have a lot of discard in the deck, but you've got some burst draw that could make this worthwhile.
Midnight Reaper - Seems an easy add. I've had good results.
Zombie Infestation - So this seems a dangerous card. Hear me out. It drops an untapped 2/2 onto the field at instant speed. Great for chump blocks, or cantripping from
Undead Augur to sculpt your hand. And your graveyard, which is great with your commander. It gives you resource from
Bone Miser too.
Fact or Fiction - I love this card, personally. In a deck like this it forces your opponents to choose between giving you a nice easy reanimation target or gas in hand, and either way works for you. This is just one card, but I personally think it's worth thinking about more cards like it - you've got great draw, in my experience it's very much worth making sure you have the right cards in your graveyard too, whether you're using your commander's ability to get them back or to cast mass reanimation.
Mindcrank - I heard you wanted to build something nasty.
Bolas's Citadel - I'm actually a little surprised not to see this card in the list already. I've seen it do disgusting things. And with your heavy scry from the command zone, it seems a great option for you.
So I think it's worth talking over your strategy too - that'll help us really refine our suggestions. What is your general plan, and how does
The Scarab God fit into it? Do you win by combat? Do you combo with Altar/ Ph Altar for death triggers? Having a clear idea of what you want the deck to do makes it lots easier to decide what gets in and what doesn't. The zombies, you've got a few options, but draw, control, finishers, all that stuff your options are myriad so it's worth thinking a little wider and making informed decisions as to what gets in.
