A complete set is one of every numbered card in a Pokémon set, including the secret rares numbered above the set count. A master set adds every reverse holo, alternate art and official variant on top, which often doubles the number of cards.
Ask ten collectors whether they have "completed" a set and you will get ten different answers. One means the numbered cards. Another will not rest until every reverse holo is in place. Both are right. They are just building different tiers.
On Binder Foundry a set binder is built around a tier ladder. Each tier contains everything in the one before it, then adds a little more. You pick a tier and your binder rebuilds around it, so the gaps you see are exactly the cards you still need, never noise. Change your mind later and the binder re-scopes without losing what you already own.
Here is how the tiers stack up on a real set, such as 151 or Prismatic Evolutions.
The Complete Set is where most collectors start: every card in the set, one printing each. That includes the secret rares, the cards numbered above the official count. A 198-card set might run to 223, and the secret rares are where the chase cards live. It is the cleanest definition of "done" and the one most people picture when they say they finished a set.
The Master Set is where serious set collectors live. It takes the Complete Set and adds every reverse holo and every official variant: cosmos holos, poké-ball patterns, alternate finishes. The alternate arts arrive here too. This is the biggest single jump on the ladder, often doubling the card count, because nearly every card has a reverse-holo twin.
The Grand master set is the top of the ladder: the Master Set plus set-tied promotional printings, staff stamps and known errors. Promos are manually assigned to a set by our team, so Grand master is curated rather than guessed. On a set with none of these linked yet, Grand master holds the same cards as Master. The same cards also work as add-ons: switch them on over a Complete or Master binder. A Master Set is already "complete" by most definitions, and Grand master is for collectors who want the absolute, every-variant, every-stamp version.
There is no correct tier, only the one that matches your time, budget and patience.
Complete Set: new to a set, or you want every card once, secret rares included. The fastest path to a finished binder.
Master Set: the definitive version. Every card, every reverse, every variant. The long, rewarding road.
Grand master: completionists only. You want promos, stamps and errors on top of a finished Master Set.
