Zombie deck focused on the Eldlich archetype.
Starting with the big stuff. Eldlich the Golden Lord is central to the deck, a great combo starter in its own right, sometimes an extender in its own right. It's also decent interaction in its own right. Even though it's searchable it is an obvious 3 of that you want to see in your hand. This is also your main boss monster. His ability to summon other zombies from the hand is sometimes key to really extending your combos with Gozuki, and his ability to send your own cards to the graveyard is similarly useful. The protection can be useful with Balerdroch sometimes. With 2 of these you can go into Superdreadnought Railcannons for easy OTKs, and with Guardian of the Golden Land that's an easy OTK against a single attack position monster.
2 of Doomking Balerdroch. He's amazing and central to the deck, serving as your main lines of interaction and best boss monster, and you do want 2 copies, but since it is so very easy to get him onto the field in this deck 2 copies will serve you well. His downside is that he requires running a Zombie world package, but there's a whole lot of upside and Zombie world is easy enough to search in this deck. With Guardian of the Golden Land you can make Dingirsu with these.
3 Uni-Zombie are your main starter. Often your best hands are more spells and traps than monsters, but this card helps mitigate hands with high monster counts. Being a level 3 tuner that can easily turn into a level 4 tuner is also highly relevant. This is basically a better Dark Grepher for Zombies, so it seems worth all 3. This makes Rank 4s, Rank 5s, Level 8 Synchros, it is a very versatile card that helps you access your extra deck. It also helps make Needlefibre.
3 Shiranui Solitaire gives us extra copies of Uni-Zombie. That's basically it, sometimes you can also search Glow-Up Bloom, but generally you want Uni-Zombie.
1 Gozuki is a little weird. I see people trying Mezuki as an extender, and the nice part of that is that it is relatively easy to get Mezuki in the bin and get the value off of it. Gozuki is an extender you want to see in your hand, however, and combos nicely with Golden Lord to get an extra zombie in the GY in exchange for protection and stats.
1 Necroworld Banshee is essential, since we're running Zombie World. Space is tight, but I could be convinced 2 of these is correct for more security in the grind game. 3 was good, but I had too many cards I wanted.
1 Glow-Up Bloom is enough. The card helps facilitate both your beaters, and is good without Zombie World and insane with it. Sometimes its weirdly actually better without Zombie World for the Golden Lord. A zombie specific better Glow-Up Bulb? I can see the appeal of modern Zombies.
Then we have a couple of "utility" zombies we can search easily off of our main Eldlixirs. Vampire Fraulein is mediocre as a hand trap, but being able to use its effect on the field off of Eldlixirs seems good enough. Additionally, you need level 5 zombie monsters to make Level 7 Synchros with off of Needlefibre - this way any search for a Golden Land or Eldlixir spell should meet the requirement.
Jack-O-Bolan is theoretically a decent value engine, and could be pretty good if you put your opponent's beater in the bin with Zombie World out. It's actually here as a form of spell-speed 2 interaction, since if you have Zombie World you can resurrect your opponent's combo pieces from the GY to deny them access to them. Not an amazing card, but the deck needed another zombie that could form an extra line of interaction off of an Eldlixir, and this was the best bet.
We're a little light on creatures and devoid of hand traps. This is because a lot of the deck's interaction comes from Trap Monsters with effects when they activate. ) 0 Ash Blossom might strike some as wrong, given that the card is a zombie monster, but I'd rather run more Golden Land traps, which double as combo pieces and from lines of interaction, than run Ash, who while reliable and powerful, doesn't actually do much for the deck, despite being a Zombie Tuner. Could be wrong, it's hard to argue that it's a mistake to run Ash pretty much ever. We do have 3 Called By The Grave, just so that our Uni-Zombie goes off, as well as being a line of interaction and helping summon the Golden Lord (if under less than ideal situations).
The black Eldlixir is pretty good on the face of it. The deck needs its Eldich cards, and the card is searchable. But surprisingly, you often want to be using your Eldlixirs on your opponent's turn anyways, so you don't end up seeing this card too often. Still, it's a 1 card starter that summons from the deck on a spell, so I'm running 3 of them. The white Eldlixir, the quickplay one, is actually often more valuable, despite seeming more limited. This deck has good grind game. 2 of them still seems enough, especially since they're searchable.
3 Cursed El Dorlando are obvious. The card searches for Eldlich and gives you a good target to send to the GY with it, and can add 1 card to your hand per turn, which is crazy good. You can't search this card, and it might get cut in game 2 for SB tech because some of those cards might be more impactful when you do see them in a given matchup, but this is a crazy starter.
2 Zombie World is enough. The deck can put the searcher in the bin or on the field very easily, and 2 should cover you for a given game. Very essential to have 2 I think.
1 Super Poly goes with the Zombie World package. You can also use Verta Anaconda to pull this out of the deck, and discarding a card is often an upside in this deck. There are more in the side for where they are good.
The Traps are in some ways a part of the deck. The Red Eldlixir, the Philosopher's Stone, is the best of them all by far, and the added redundancy helps keep the deck's engine humming. Like the other Eldlixirs, you can banish this from the gy to set a Golden Land card.
Conquistador of the Golden Land is a clear 3 of. Searching for an Eldlixir card in the end phase by banishing it keeps the deck rolling in resources, and the ability to destroy monsters is key. This is simultaneously interaction and a combo piece. It's brother, Huaquero, is a D.D. Crow on a trap. Not quite as good as a Called by the Grave in terms of interaction, but it's also a trap monster and a combo pieces. The weakest of these is guardian, but it might be key to some OTKs and its searchable, so 1 of makes sense. The last Golden Land card is the Everglorious Golden Land, a counter-trap that Omni-negates but requires a tribute. It's a searchable countertrap that omni-negates so it has to make the cut as at least a 1 of. I could be persuaded 2 of these is correct, the card is just solid.
Side Deck is a bunch of options to bring in going second to break boards, as well as the Adelantado which seems good in grindier matchups, and a Mystic Mine package. Mystic Mine is cool here, since you can get rid of it by searching zombie world. This is just a pile of cards that will win you games going second against creatures/spellw and traps, and then Adelantado.
You could run Pot of Extravagence, and it is hard to argue that it would be wrong, but I just didn't like how Extravagence felt in the deck. I like running a bunch of situational 1 ofs in the extra deck rather than piling in multiples of the stuff I need to see. 2 cards is great, but you need access to a bunch of stuff for different situations. I guess you could consider Magicians' Souls, since there are synergies there. But I don't know, the card is good, but I feel overrated without those synergies. They're believable here, since your want your spells/traps in the GY, but personally I like running them alongside Spellcaster Synergies in decks that want cards in the GY rather than running them as just generic draw support. They meet 1 of those requirements, but not both.
EDIT* Testing Performapal Popperup. Synergies seem high in this deck, actually, like a Magicians' Souls without the bricks. Also trying a single Ghost Ogre, to get an extra interaction off of Needlefibre. Reasonable, since if you see it it's a valuable hand trap.
So far, Popperup ranges from hand neutral to a +5 depending on your hands, and provides reasonable fixing even in the low end. It is easy to lose 3000-4000 life points off of it, which might mean taking them out if you're worried about going to time. I love the +5 hands enough to take the hand neutral ones, but you could be excused for running Extravagance instead. I think Popperup is better than Magicians' Souls in the deck by far however. The more I test with it the better it feels. Ranging from being an Upstart Goblin to a +5 is a pretty sweet consistency boost.
Dropping Dingirsu for Divine Dragon Knight Felgrand. There are a few reasons - it gives me one more monster negate, it protects monsters from more kinds of effects, and most importantly, you can detach one material at any time to get your Doomking back in the graveyard.
Cut Jack-O-Bolan. He's good, but space is tight, and Fraulein is more essential to make Zombie Necro.
Added Instant Fusion with just Millennium-Eyes, as a 4th way to protect against Ash.