Calypso Cards

Calypso Cards does not offer a lot of details for potential submitters, but they are open to submissions (copy or art).  No payment terms are specified, and their guidelines page says they'll only contact you if they decide to use your idea.  Submissions and inquiries should be made via email.

Calypso currently wants greeting card ideas for their Selfish Kitty line: "... a humor line which is edgy but not cruel or degrading."