Henna designs from different regions of the world:

Around the world there are numerous types of henna designs and styles ranging from geometric to floral to intricate grids and even animal and human faces. Henna is used for joyous occasions, weddings, parties, bridal and baby showers, and religious holidays. I'll take you through some types of designs (though certainly not all of them).
Moroccan/North African Designs (below): Moroccan patterns are geometric and look very calculated like algorithms converted into design. Much of old islamic art from North Africa is geometric and vegetal in nature (on mosques, doors, even palaces and fancy cutlery, some examples include the mosque at Timbuktu and intricate designs on the Fatimid mosques in Egypt). There are lines, diamond shapes, squares and triangles in Moroccan designs, criss-crossing and intertwined lines creating depth in a palm.

South Asian Designs (below): Indian patterns are very thin and intricate; they often containing numerous types floral patterns with leaves and paisleys. During weddings, husbands and wives names are inscribed in the henna design and it becomes a game to try and find them. Faces and animals are incorporated in henna designs, sometimes depicting a scene of a wedding itself. Animals like the peacock and elephant are drawn on to hands for beauty as well as luck.

Middle Eastern/Arab Designs (below): Arab designs are very big, usually floral in nature with dots and lines. The designs are use alternating thick and thin lines with floral patterns filled in with thin lines. There are grids and chevrons and thicker borders with thinner interior lines. Sometimes the designs can look similar to Indian styles.

Not mentioned here are Sudanese styles of henna designs. I have not learned them yet but when I do, I will mention them on this blog. Let me know what your favorite styles are!