Masterpiece Series

The Masterpiece Series is a collection of promotional Magic reprint sets of foil cards that originally were randomly inserted in boosters of different blocks or standalone sets. The reprints don't appear in the main sets themselves. Each individual block or set had its own name for its collection. However, taken together, these collections are referred to as the Masterpiece Series.

The Masterpiece Series was created after the commercial success of the Zendikar Expeditions. Originally envisioned to appear with every block, the appearance of the Masterpiece Series was quickly scaled back with the introduction of the Three-and-One Model because R&D realized that producing one for each set would eventually lead to the overall quality level dropping below their standards. Masterpieces briefly lived on in the form of Mythic Editions, which in turn were to be replaced by the Secret Lair products.

When Expeditions returned for Zendikar Rising, they were transformed into Box toppers.

Description
The original format was envisioned as follows:
 * Each block has approximately 50 Masterpiece Series cards. Although they may appear in non-English products, all Masterpieces are printed in English only. The card versions of the Masterpiece Series exist at a rarity higher than mythic rare, but slightly less rare than a foil mythic rare. For example, for Kaladesh roughly 1 out of every 144 boosters contains a Masterpiece (technically 1:2,160 cards.) These ratios may differ for other sets. For Amonkhet it is 1:1,935. The original versions of cards appearing in the Masterpiece Series may also have appeared in rarities other than mythic rare.
 * The Masterpiece Series, both in presentation and card selection, is tied thematically to the world appearing in the block or standalone set. Masterpiece cards can have keywords that do not otherwise appear in the set they are printed with. To date, this criterion has meant that each reprint has received new art that reflects the plane of the relevant set. Furthermore, Masterpiece-specific card frames change from block to block and are created to match the feel of the world/set. Masterpiece themes are not always related to card types (e.g., lands, artifacts). Similarly, the expansion symbol for each Masterpiece set is block-specific but distinct from the sets in that block. All Masterpiece Series sets, but for the retroactively-added Zendikar Expeditions, have the set code MPS.
 * In addition to physical print, Masterpiece cards appear in Magic Online but are not redeemable and are not counted as part of the set. They do not, however, exist in Magic Duels.
 * Masterpiece cards can be played in any Limited format they are opened in and in any Constructed format in which the card is already legal.

Sets

 * Zendikar Expeditions (retroactively added ) all lands.
 * Kaladesh Inventions all artifacts.
 * Amonkhet Invocations the Amonkhet gods, their magic and their servants.
 * Ixalan Explorations (cancelled) searching spells.

The Guilds of Ravnica block consequently experimented with Mythic Editions, which filled a similar role. After  War of the Spark this morphed into Collector Boosters / Booster Fun. The difference is that the Booster Fun cards are versions of cards in the set, not from outside of the set. For cards outside of the regular set, the Secret Lair Drop Series was developed.


 * Zendikar Rising Expeditions all lands again.

The Mystical Archive of Strixhaven: School of Mages (all instants and sorceries) is very similar to the Masterpiece Series, but the cards appear more frequently in the boosters of the main set and have a more profound influence on the Limited environment.