Jumble Chess

From BoardGameGeek:

Jumble Chess is a two-player chess variant played with a standard chess set and a deck of 48 modifier cards. Each modifier permanently grants a new ability to its owner's pieces, so the two armies gradually drift away from standard chess and from each other. The game follows the normal rules of chess. The modifiers are sorted into three tiers of increasing strength (Classic, Gold, and Radiant), and each tier is shuffled into its own face-down pile. At the end of their 1st, 8th, and 15th turns, each player draws three cards from a single pile (Classic first, then Gold, then Radiant), keeps one, and returns the other two to the bottom of the pile. The chosen modifier takes effect immediately and stays active for the rest of the game. Classic modifiers make small adjustments, such as letting bishops swap places with a friendly piece in their line of sight, or letting pawns promote from the sixth rank. Gold modifiers are stronger, for example allowing pawns to capture straight ahead. Radiant modifiers have the largest impact: queens that can also move like knights, pieces that pass through friendly pieces, or an alternative way to win by giving check six times. As in chess, a player wins by checkmating the opposing king, and the usual draw rules apply. -description from the publisher