Commander Cards in Cube: Supplemental Sets, Masters, UB

Commander cards in cube are a question every owner answers eventually, usually the first time a friend hands them a Commander-only card and asks why it is not in the list. The answer is that supplemental sets follow different rules from Standard sets, both in how they are designed and in how a cube should read them. Some of the most important cube cards of the last decade came from non-Standard products. Most cards in those same products are built for four-player, 40-life games and do nothing in a draft. This article is how we sort them.

For the method itself, see how we evaluate new cards. This is about how the method changes when the set was never meant for Standard.

What counts as a supplemental set?

For cube purposes there are four families, and they behave differently.

Since Final Fantasy in 2025, Universes Beyond sets have mostly been Standard-legal: Final Fantasy, Spider-Man and Avatar in 2025, then Teenage Mutant Ninja Turtles, Marvel Super Heroes and The Hobbit in 2026. They draft like Standard sets, so review them as such. Earlier Universes Beyond sets like Warhammer 40,000 were Commander-only, so they belong in the first row. Check which kind you are holding before applying a rule.

Why do Modern Horizons sets matter most?

Because they are the only product Wizards designs directly for the formats cube borrows from. Among others, MH2 produced Ragavan, Nimble Pilferer; Solitude, Grief, Fury, Subtlety and Endurance; Urza’s Saga; and the enemy fetch land reprints. MH3 produced Phlage, Titan of Fire’s Fury; Psychic Frog; the flare cycle; and the allied fetch land reprints. A typical Standard set gives a Legacy-power cube two to four keeps. A Modern Horizons set can give it ten to fifteen, and it will also shift the power of the slots those cards enter.

That is both the appeal and the warning. When Solitude and Fury arrived, white and red got a free removal spell apiece that could be pitched on turn one. Cubes that added them without re-examining the rest of the slot found their aggro decks running into a free Swords on turn two. If you add Modern Horizons cards, add them with the slot method and watch the next three drafts closely. The free-spell question in particular has its own article in this batch.

Our house rule: Modern Horizons sets get a full review, every card, the same as a Standard set. No other supplemental product does.

Which Commander cards work in a cube?

The filter is simple and brutal: does the card do its job against one opponent at 20 life? Most Commander designs fail it. A card that triggers on each opponent, drains each opponent, or scales with the number of players is doing a third of its work in cube.

Cards from Commander products that have passed the filter in Legacy-power cubes include True-Name Nemesis and Toxic Deluge, both from Commander 2013, and Dockside Extortionist from Commander 2019, in cubes with enough artifacts and Treasures. Note what they share: none of them mentions a commander. Cards that do lose text in cube. Arcane Signet makes no mana, because the rules leave a missing commander’s color identity undefined, and the Commander 2020 free spells like Fierce Guardianship are free only while you control a commander, so in a draft Fierce Guardianship is a three-mana counterspell for noncreature spells.

What fails: anything with “each opponent” that is costed assuming three of them, anything that needs a commander in the command zone, political cards, monarch and initiative cards unless your cube is specifically built for them, and most legendary creatures above four mana. A six-mana legend that is a Commander house favorite is almost always a five-mana cube card with an extra mana on it.

Practical process: when a Commander product releases, read the new cards once, flag anything at three mana or less that works in a two-player game, and run those through the slot comparison. Expect zero to two keeps per release. Expect zero most of the time.

If this is useful, the newsletter sends more like it.

What do Masters sets give a cube?

Nothing new, and that is the point. A Masters set is a reprint set. Its value to a cube owner is price: a reprint usually pushes a staple’s price down for a while, and if your list has a budget gap, the weeks after a Masters release are a good time to fill it.

Two habits make Masters sets useful. Keep a want list of cards you would run if they were cheaper, so the reprint announcement turns into a shopping list. And do not confuse a reprint at a new rarity with a new card, except in one case: a staple reprinted at common or uncommon becomes legal for Pauper and Peasant cubes. Those owners should read every Masters set’s common and uncommon sheet, because a single downshift can be the best card their format gets all year.

How should a cube handle Universes Beyond?

This is a house decision, and the right answer is whichever one you make once and apply to every set.

The case for including them: the best card for the slot is the best card for the slot, and the 2026 crossovers were Standard-legal and designed for Limited. Smaug the Magnificent was a keep in our Hobbit review, and The Mind Stone earned a test slot in our Marvel review. The case for excluding them: a cube is a curated object, and a table of Lorwyn faeries, Ravnica guilds and Marvel heroes reads as a pile rather than a set. Some owners want the cube to look like one game.

A middle path several cubes use: allow Universes Beyond cards only in their “Universes Within” in-universe printings where one exists, and skip the rest. That keeps the look consistent and costs a few cards.

Whatever you choose, write it in your primer, because new drafters will ask. The earlier Universes Beyond sets that were not Standard-legal, like Warhammer 40,000 and the Doctor Who decks, follow the Commander-product rules above and produce very few cube cards regardless of policy. The Lord of the Rings set, which was designed to be drafted, produced several, The One Ring and Orcish Bowmasters among them.

How do supplemental cards change set reviews?

Three adjustments to the regular process.

1. Review by product type, not by release date. A Standard set, a Commander release and a Masters set in the same month are three different jobs: full review, cheap-card scan, and shopping list. Doing them as one review wastes time on cards that were never candidates.
2. Keep the power-tier column honest. Supplemental cards are often tuned for a power level above or below your cube. Dockside Extortionist is a powered-cube card and a mistake in a Modern-power list. Note the tier in the log entry.
3. Watch the free spells and fast mana separately. Almost every supplemental card that broke a cube did so by being free or by being mana. When a candidate is either, run an extra draft before committing. The structural concerns are in our fast-mana and card-advantage articles in this batch.

The log format from our set review method handles all of this with one extra column for product type.

FAQ

Should Commander cards be in a cube at all?

Yes, when they pass the two-player test. Cards like True-Name Nemesis and Dockside Extortionist work in a draft deck against one opponent. Cards that need three opponents or a commander do not, and they are most of what Commander products print.

Are Modern Horizons sets too strong for cube?

For some cubes. A Modern Horizons set can add ten or more cards to a Legacy-power list and shift the power of whole slots. Add them with the slot method and watch the next three drafts; cut the ones that end games before interaction matters.

Do Masters sets add new cube cards?

No. They reprint existing cards. The exception is a rarity downshift, which can make a card newly legal for a Pauper or Peasant cube.

Should my cube allow Universes Beyond cards?

Decide once and write it down. Including them gets you the best card for each slot; excluding them keeps the cube looking like one game. Either is fine. Changing your mind every set is not.

Keep up with every product type

Subscribe to The Ludarium newsletter for new cube pieces, and to hear when Cube Commonwealth, our Indianapolis cube group, sets its first night as part of The Ludarium. The game is the reason. The people are the point.