Pop-up cards are normally cards that, once opened, have a picture coming outward, giving the reader a surprise. Pictures and printed messages in greeting cards come in various styles, from fine art to humorous to profane. Non-specific cards, unrelated to any occasion, might feature a picture (or a pocket to paste in a personal photograph) but no pre-printed message. Paper Pop Cards has a patent for detachable pop-up cards which lets the pop-up be saved as Keepsake.
DLTK's Standard Printable Greeting Cards - these are the cards we've always had on the site. They include birthday cards, thank-you cards, birthday invitations and a wide variety of other types of cards you can print in either color or B&W. Over 1000 cards in over 100 different themes are available. You cannot type your own messages on-line on these ones.
These are greeting cards for the budget conscious. There are two common formats for reusable cards. Firstly, there are cards with slits in them positioned to hold pages. Secondly, there are notepad style cards where pages stick to the back of the cards. The pages that have been used for reusable cards can be removed after being received and fresh pages can be used to reuse the cards.