auper is a Magic Online format in which all cards used must have been printed at the common rarity in a Magic Online set or product. Common promo cards are only legal if the card has been printed at the common rarity in a set or product. Other than that, the usual rules for Constructed decks apply (a minimum deck size of 60 cards in the main deck, an optional 15-card sideboard, and so on). If a common version of a particular card was ever released on Magic Online, any versions of that card printed at other rarities are also legal in this format.
Example: Counterspell was a common card in the Seventh Edition core set, which was released on Magic Online. Counterspell was reprinted in Masters Edition II with an uncommon expansion symbol. Both versions of the card can be used in the Pauper format.
Example: Hymn to Tourach, another uncommon from Masters Edition II, is not legal for use in the Magic Online Pauper format. Even though Hymn to Tourach was printed as a common in the Fallen Empires set, that set was never released on Magic Online
The Pauper banned list is: