The 12 suits of the free, printable, 162-card Rainbow Deck might be useful for piecepack game designers who would like to expand the 12 suits made by combining a standard piecepack, playing cards piecepack, and seasonal piecepack.

piecepack suitMesomorph colorJCD colorSuggested Rainbow Deck colorMnemonic
Sunsredredredsame as basic piecepack
Crownsyellow or greengreenyellowsame as basic piecepack
Arms (JCD: Anchors)bluebluedark bluesame as basic piecepack
Moonsblackblackblacksame as basic piecepack
Spring (Flowers)light bluepurplelight bluesame as original Mesomorph
Summer (Fish)purplelight bluedark purplesame as original Mesomorph
Autumn (Leaves)orangeorangeorangesame as Mesomorph and JCD
Winter (Snowflakes)whitewhitegrayclose to Mesomorph and JCD
Heartsredredpinkcolor of love; pink = light red; goes with light purple (other red suit)
Spadesblackblacklight greenblade of grass; both black suits are green
Diamondsredredlight purplegoes with pink (other red suit)
Clubsblackblackdark greenclover; both black suits are green

I had originally mapped Spring onto light purple and Diamonds onto light blue, but MartyHaleEvans made a good case for reversing these (see comments). Most of the original colors of the basic and seasonal piecepacks are now preserved. However, the playing card suits are now red(dish) and green instead of red and black.

Like the JcdPiecepack, the Rainbow Deck is divided into light and dark suits. Unfortunately, there doesn't seem to be a sensible, non-arbitrary way to map the light and dark suits of the Rainbow Deck onto the JcdPiecepack.