Sizes range from small folded A2 cards (5.5" x 4.25" and 4.75" x 6.13") to standard pop-up sizes (about 8" x 6") and up to an oversized folded giant card (16.5" x 22").
Most are printed on heavy card stocks (including heavyweight 270gsm and premium cardstock, with some FSC- and SFI-certified options). A few pop-up designs use recycled materials, and one oversized option is printed on corrugated plastic.
Listings commonly note suitability for birthdays, weddings, anniversaries, thank-you, get-well, sympathy, encouragement, friendship/gratitude, Valentine's Day, teacher appreciation, and other holidays.
Many envelopes use peel-and-stick flaps (rather than lick-and-seal) and are described as heavyweight and often hand-embossed for a polished finish.