PLAYTEST CARDS
Playtest cards are used by game designers and developers to test their game prior to publication. Frequently these cards are distributed to playtesters who play with them and report back with their impressions and results. Because of the need for frequent revision, playtest cards are typically photocopied onto card stock or printed on stickers that are affixed to production cards.
This article is principally about the five sets of playtest cards for Magic: The Gathering created prior to the publication of First Edition (commonly known as Limited Edition Alpha & Beta) that influenced its final design. In chronological order, these playtest card sets are known as alpha, beta, gamma, delta and epsilon.
ALPHA PLAYTEST
For the first playtest of Magic, Richard Garfield made a single 120-card deck with all five colors plus artifacts and lands. The players split this single deck into two and each took half to use as their deck to play the game. Games were played for ante, and continued until one player had an unplayable deck. These cards were on yellow card stock and were all created by hand. Many had hand-drawn images, with the rest having only hand-written rules text and no images. Richard Garfield currently owns all of these alpha playtest cards.
BETA PLAYTEST
Beta playtest was the first playtest where players received random, person collections of cards. It occurred in several phases. Like alpha playtest cards, early beta playtest cards still show creature strength as only a single number, but later beta playtest cards show the separate power and toughness numbers we know today. Casting costs were expressed a bit differently throughout playtesting, using a format where the number represented the total number of mana required (not just the number of mana of any color required), followed by colored circles (or letters starting with gamma playtest) indicating how many mana were required to be of specific colors. For example, the beta playtest Fairies shown required a total of one mana to cast, which had to be green mana, exactly as the card Scryb Sprites was eventually published. Cards were photocopied rather than created completely by hand as in Alpha playtest. Colored mana is indicated by a circle hand-drawn with a colored marker, either freehand or by filling in a small blank circle that was printed on the card. Some cards in beta playtest contain illustrations appropriated from various printed publications, while others have hand-drawn images or only rules text as in Alpha playtest.
Beta playtest comprised 60-card decks for roughly 20 different playtesters. It was produced on whatever leftover card stock Richard could procure, which was in a variety of different colors. No complete list of Beta playtest cards is known. There are known physical copies of approximately 125 different cards.
GAMMA PLAYTEST
With approximately 40 playtesters, Gamma was the largest playtest, in terms of number of playtesters as well as total number of cards produced. Gamma is the first playtest that closely resembles published First Edition, containing approximately 250 of the 295 cards that were ultimately published. Because of the increased work that would have been required to hand-draw colored circles on all of the cards, for this and subsequent playtests casting costs use the letters "W", "U", "B", "R", and "G" to represent colored mana requirements.
All Gamma playtest cards are illustrated, mostly with appropriated images. All Gamma playtest cards were printed on the same light gray paper stock. As with other playtest cards of this era, they measure 2-1/8" x 2-3/4" in size, as they were produced by making 8-1/2" x 11" photocopies and cutting each page into 16 cards. A complete spoiler of gamma playtest exists because Richard retained the sheets that he used to produce Gamma playtest cards. Some Gamma playtest cards have the image of a unicorn stamped on the back (which would otherwise be blank), which indicated that these cards were part of the first playtest league.
DELTA PLAYTEST
This playtest was similar to Gamma in the number of different cards it contained, but the number of cards produced was smaller because it was only playtested by a fraction of the Gamma playtesters. For the most part, illustrations on these playtest cards are identical to those used in Gamma playtest. In fact, many cards in Delta playtest are identical to cards in Gamma. Many others have only small changes such as changed casting cost, as the card design was satisfactory but there was debate as to how well balanced the card was in the context of the rest of the card set.
However, there were also some new designs that first appeared in Delta which were eventually published in First Edition, the most notable being the dual lands, but also including cards such as Spell Blast and Conservator. Delta playtest cards are printed on orange card stock. No complete list of Delta playtest cards is known. There are known physical copies of only about 150 different cards as many were destroyed after the playtest was completed.
EPSILON PLAYTEST
Epsilon playtest was similar to Delta insofar as it contained many card that were either identical or similar to those found in Gamma playtest. The first known playtest copy of several First Edition cards is from Epsilon, for example Orcish Artillery, Dragon Whelp, Dwarven Demolition Team, Paralyze and Lance. But because we do not have a complete list of cards from Delta playtest, it is uncertain whether these cards first appeared in Delta or Epsilon. The majority of Epsilon playtest cards used new illustrations not seen in prior playtests, though a number of the playtesters' favorite illustrations remain unchanged. Epsilon cards were printed on white card stock which was somewhat more durable than used previously, giving them a crisp, aesthetically appealing look relative to other playtest editions. Like Delta, there is no known complete list of Epsilon playtest cards, though physical copies of about 230 different cards are known.
"FIVE MAGICS" PLAYTEST
In 1982, a decade prior to the design of Magic: The Gathering, Richard Garfield designed a game that he called "Five Magics." 
Five Magics was not a trading card game but rather a traditional card game with some themes and cards that resemble Magic: The Gathering. Five Magics was never published, but almost 10 years later when Richard began designing the first trading card game, he returned to Five Magics as a source of inspiration for the game that eventually became Magic: The Gathering.