3D lenticular printing can be used for greeting cards,in addition to that,it can  be used for a very wide field.
Advertising industry: 3D advertising light boxes, outdoor advertising, 3D posters etc;
Promotion industry: badges, hang tags, mouse pads, coasters, magnets, keychain, toy stickers, calendars, notebook, signage, puzzles, photo-album, can coolie, hats, bookmarks, bags, etc;
Decoration industry: Decoration painting for companies, public places, home, etc;
Tour industry: 3D souvenir cards, 3D crafts, 3D tickets, etc;
Printing industry: 3D greeting cards, 3D Christmas cards, post cards, book covers, diary covers, CD/DVD covers etc;
Publishing industry: the covers of notebook, CD/DVD, books and magzines.
Packaging industry: High-class and anti-fake packaging boxes for cigarette, wine, spirit, whisky, cosmetic products, make-up products, food, etc... Just say it. You can use 3D pictures anywhere you need pictures.
Manufacturing industry: electric applications, toys, furniture, garment, play station, etc;
Photography industry: 3D wedding dressed photo, artistic photo etc.
In fact, as long as there are images,  there may be 3D images