Summary
Usually, when a card is released inMarvel Snap, players find a way to make it fit within the existing archetypes. While that certainly was true for Baron Zemo, this card debut also saw the birth of a new way to play the game: the mill decks.
Now, mill decks aren’t anything new to the world of card games, but there wasn’t enough support for them within Marvel Snap for it to be viable. The introduction of Baron Zemo finally tipped the scales, creating a deck that can remove all cards from your opponent’s deck and hand; just remember to snap before they retreat.

8Yondu
Eliminate All Low Cost Cards
Both Yondu and Baron Zemo target similar cards within your opponent’s deck, that is, their lowest costing cards. But while Baron Zemo grabs that card and puts it into play, Yondu destroys the card instead, and without triggering any destruction mechanics like Wolverine or Bucky Barnes.
Any cards destroyed by Yondu will still count as power added to Knull or be revived by the Valley of the Hand location.

You will naturally play Yondu before Baron Zemo, simply due to their costs, but you should also do so even when you can play them both at the same time. That way, Yondu will destroy their smallest card, improving the chances of Zemo getting a higher quality pull from their deck.
7Cable
Taking A Card For You
Cable can have a huge impact on many games, all depending on what he pulls. Sincehe draws a card from your opponent’s deck, not only will you get information on what they are playing, but you might also get a key piece of their combo, all without them knowing.
Yet that was never enough to include him in most decks, but here the idea is iteration: you want to pile up as many milling cards as possible, removing your opponent’s entire deck in no time. Since decks in Marvel Snap are so small, just a few cards are enough to get your opponent in a situation where they simply cannot win.

6Gladiator
He’s Itching For A Fight
Gladiator is already a good card, putting up huge power on the board while having a devastating effect: he puts a card from your opponent’s deck on their side, and if Gladiator has more power, that card is destroyed. The chances that you’ll end up helping your opponent are rather small.
With Baron Zemo and the gang, you need to play Gladiator a bit differently, but he works for the better. Playing Gladiator before Zemo is ideal, otherwise Zemo (or even Yondu) raises the chances of Gladiator pulling a bigger card.

5Spider-Ham
Negating Effects
While Baron Zemo works well with cards that mill your opponent, you have few ways of avoiding them from still drawing their powerful cards. Spider-Ham fills the role of countering what they already drew, transforming their leftmost card in hand into a pig, meaning they have the same power but no ability.
Spider-Ham is best played late, that way you improve your chances of hitting a higher priority target. However, that all depends on your hand; if you notice you already have a nice curve for the following turns, playing Spider-Ham in turn one is the best course of action.

4Maximus
His Ability Is Often Ignored
Maximus has a lot of power for his cost, but he comes with a downside: he draws two cards for your opponent. While bad, that effect can easily be ignored here, since if either him or Gladiator are played when your opponent has no deck, they might as well have no ability.
There’s also some use in forcing your opponent to draw cards. That way, you can improve the chances of both Yondu and Baron Zemo hitting higher priority targets; it isn’t a sure bet, but improving odds is everything when dealing with random chance.

3Absorbing Man And Grandmaster
For The Greedy Players
With so many powerful on-reveal cards, making them happen again sounds like an ideal scenario. Yet you need to be careful since repeating Baron Zemo’s ability can quickly fill your side of the board, and once your opponent runs out of cards, repeating the effect does nothing.
Wong and Odin are great with on reveal cards in general, but they don’t fit at all with what Baron Zemo is trying to do.
Grandmaster sends an on–reveal card to the middle location, making their effect happen again, while Absorbing Man copies the last on-reveal you played. If used carefully, you may reiterate many of your powerful effects to ensure your opponent has nothing to play, making Absorbing Man and Grandmaster great additions to a Zemo build.
It’s best that you pick only one of the two, if any, so you don’t reiterate too much. That way, you leave room on your deck for powerful finishers, like Doctor Doom to go wide or Red Hulk to go high at a single location.
2Shadow King And Shang-Chi
The Counter Duo
No matter what you do, your opponent will still be able to play some cards, so you need a way to deal with them. Shang-Chi is always a great addition, making short work of their big plays, and makes Gladiator a safer play than usual (since you can usually kill whatever Gladiator can’t).
Depending on the meta, you can replace Shang-Chi with Enchantress, but the counter card you can’t avoid having is Shadow King. Not only is he great against most buffing decks, he also works perfectly with Spider-Ham, since if you use Shadow King against a Pig, their power goes to zero.
1Doctor Octopus
Snap Before You Play This
Doctor Octopus has always been a tricky card to use since his effect can be used against you. He pulls four cards from your opponent’s hand into their side of the board, which often beats Octopus in power and leaves you with only one turn to come back.
Yet with Baron Zemo, you will have already milled their deck by the time you play the Doctor. This means that, quite often, those four cards are all they had left in hand, letting you follow up with Shang-Chi or even Shadow King to finish the game.