TLDR: Start a custom Limited set with commons because commons establish the gameplay players encounter repeatedly. They define early pressure, blocking, removal, mana use, mechanic visibility, and the likelihood of board stalls. Build a common skeleton around environment jobs, run all-common playtests, and add higher rarities only after the basic games are functional and recognizable.
The central challenge in custom mtg set commons design is resisting the urge to begin with the mythic rare that inspired the project. That mythic may express the setting, but it cannot tell you whether a typical game has useful plays on the early turns, whether aggressive decks can attack, or whether every board eventually becomes an immovable pile of creatures.
Commons can answer those questions because they form the repeated foundation of Limited play. Wizards design writing describes commons as the bulk of Limited gameplay, a major carrier of set themes, and the recommended place to begin early design and testing. Its Common Knowledge design article also recommends testing with commons before the other rarities complicate the picture. If you need to establish the larger vision first, outline the themes and archetypes with a custom MTG set design framework, then return to commons to determine whether that vision produces good games.
A common skeleton is not a list of favorite card ideas. It is a list of jobs the environment needs performed. Individual cards can change repeatedly while the jobs remain stable.
Start by identifying the functions your commons must provide. The exact distribution depends on set size, collation, player count, and intended format, so avoid treating an official set skeleton as a mandatory quota. Wizards likewise presents its Play Booster skeleton as a starting point that changes according to the needs of each set.
| Common-level job | Question it should answer |
|---|---|
| Early creatures | Can players develop the board or contest an early attack? |
| Midgame creatures | What creates profitable attacks, blocks, and trades? |
| Closing threats | How does a deck convert an advantage into a win? |
| Evasion | Can a game progress when the ground is crowded? |
| Removal and interaction | Which permanent and spell types can each color answer? |
| Combat tricks | What uncertainty makes creature combat consequential? |
| Mana smoothing and fixing | How reliably can intended decks cast their spells? |
| Theme enablers | What lets the set’s named themes function? |
| Theme payoffs | Why should a drafter commit to those themes? |
| Utility answers | What prevents artifacts, enchantments, tokens, or graveyards from becoming structurally unchecked? |
Not every job needs an equal number of cards, and not every color performs a job in the same way. A color might answer a large creature directly, temporarily remove it from combat, race it with evasion, or require two cards to trade for it. Those differences preserve color identity while still giving decks ways to participate.
The speed of a Limited environment is not set by declaring it “fast” or “slow.” It emerges from the relationship among early attackers, available blockers, removal costs, combat tricks, life gain, evasion, and late-game rewards.
Suppose aggressive two-mana creatures regularly attack through defensive creatures at the same cost. If removal is also efficient, players who stumble may have little time to recover. Reverse the relationship—give common blockers high toughness while making evasion scarce—and the set may produce long stalls. Neither result is automatically wrong. The problem is reaching it accidentally.
Choose baseline creature sizing by asking what should happen in combat rather than copying another set’s numbers. For each point on the curve, consider:
Test the relationships as a group. Increasing one creature’s power may look like a small card-level change, but repeating that adjustment across several commons can accelerate the entire format. Likewise, one efficient defensive creature may suppress multiple aggressive designs if it appears frequently.
There is no universal correct number of common removal spells. The useful questions are what each color can answer, how efficiently it can answer it, and which threats are intentionally difficult to handle.
Map the main threat categories in your set: small creatures, large creatures, wide token boards, evasive threats, artifacts, enchantments, graveyard engines, combat tricks, and any set-specific permanent type. Then check how each color responds. The response does not always need to destroy the threat, but it should produce an intentional play pattern.
Broadly playable interaction keeps more draft picks and draws relevant, while narrow answers need a real environmental reason to exist. Wizards’ Play Booster design discussion similarly emphasizes assigning interaction roles by color and avoiding an excess of situational cards that frequently lack targets. A narrow common is justified when its target appears often enough, when sideboarding matters to the format, or when the card has a useful fallback mode. Otherwise, it may simply be a dead card disguised as texture.
Removal efficiency must also be judged against threats. Expensive interaction in a format full of cheap snowballing creatures is very different from expensive interaction in a slower environment. Conversely, cheap unconditional removal can make investing mana in large creatures unattractive. Review threats and answers together rather than balancing either category in isolation.
A theme described in the set document is not necessarily a theme players will encounter. It needs enough simple common cards to appear during drafting and gameplay.
Wizards uses “as-fan” to describe the expected frequency with which a feature appears when a player opens a random booster. Moving cards among rarities changes that frequency. You do not need a formal probability model for an early custom set, but you do need to consider encounter rate.
If the set is about artifacts but most artifact rewards are uncommon, a typical drafter may not perceive artifacts as foundational. If a named mechanic appears on only a few commons, players may struggle to assemble a deck around it. On the other hand, placing a complicated mechanic on many commons can make every pack and battlefield harder to process.
Give each central theme common representations that are frequent, legible, and useful without a rare payoff. A theme enabler should do a normal Limited job while supporting the theme. For example, a creature that creates a set-specific resource might also provide an acceptable body. A payoff might offer a modest bonus rather than becoming worthless whenever the theme fails to appear.
Frequency assumptions must match the actual format. Booster Draft depends on collation and repeated pack openings. A singleton cube may expose a mechanic less consistently, even when it occupies the same percentage of the card pool. Sealed and curated pools create different distributions again. If you are building a singleton environment, the basic structure of an MTG cube is a more useful starting point than blindly applying booster-set rarity assumptions.
Simple commons do not have to produce simple decisions. A short combat trick can create questions about attacking, blocking, mana use, and bluffing without requiring players to reread several permanents every turn.
Wizards’ New World Order discussion separates comprehension complexity, board complexity, and strategic complexity. Comprehension complexity concerns how difficult a card is to understand. Board complexity concerns how difficult the battlefield is to track. Strategic complexity concerns the depth of decisions a card creates. For common design, the goal is usually to constrain the first two without eliminating the third.
Watch especially for commons that create persistent counters, conditional bonuses, repeated triggers, unusual zones, or multiple activated abilities. Any one of those can be manageable. Repeating several across the common sheet can create a battlefield where players spend more effort auditing state than making plans.
Move a design to uncommon when it requires too much explanation, creates repetitive board tracking, dominates games when drawn in multiples, or represents a reward that should not appear constantly. Rarity is not merely a power ranking. It also controls frequency, complexity, and how often a play pattern shapes the environment.
An all-common test strips away rare bombs and elaborate build-arounds so you can see whether the environment’s basic gameplay works. Wizards recommends this kind of early test before higher rarities obscure foundational results.
Build rough decks or pools from the current common sheet. Temporary, highly readable cards are sufficient; polished art and finished flavor text do not improve the test. If needed, use blank custom-card templates for early playtesting so revisions remain quick.
During each game, record environment-level observations rather than only wins and losses:
Change groups of cards only when the diagnosis calls for a systemic adjustment. If every game stalls, weakening one blocker may not solve the underlying relationship among toughness, removal, evasion, and finishers. Form a hypothesis—such as “defensive creatures stabilize too efficiently”—then revise the smallest connected group that can test it.
Once the common games produce the intended pace and recognizable themes, add uncommons to sharpen archetypes and provide more specialized rewards. Add rares later to create unusual stories, larger build-arounds, and effects that should not define every game. For subsequent full-table tests, use a repeatable custom MTG draft playtesting process and track changes between versions.
The first common sheet does not need to be elegant. It needs to expose the environment. If the set is meant to reward combat, commons should create meaningful attacks and blocks. If it is built around a mechanic, players should encounter and understand that mechanic without waiting for a rare. If it promises multiple archetypes, the common cards should supply the basic material those decks require.
Only after those relationships work should you invest heavily in polished frames, finished illustrations, or physical production. If the project eventually becomes a reusable draft environment, printing the custom set as a cube can be a later step—but physical presentation cannot repair a weak common foundation.
Design the jobs, test the repeated play patterns, and revise the environment before decorating it. Your next version should answer one concrete question: do the commons already produce the speed, interaction, theme visibility, and decision-making that the finished set is supposed to deliver?
