Collecting Egg Cups is Unique and Beautiful Hobby. 
They're not a recent invention. A silver egg-cup was discovered in the ruins of Pompeii, preserved under lava and ash when Mount Vesuvius erupted in 79 A.D. and completely buried the city. Turkish mosaics found in the city showed scenes of people dining, many of whom were using eggcups.
Egg-cups were used in England during the Elizabethan period ( 1600’s. ) The ruling classes ate their eggs in silver eggcups, the poor people used wooden ones. And if you're a handy type, you could make one like this, from foraged wood.
 "Louis XV often entertained his courtiers by “beheading” the egg in his eggcup with one slice. Ironically, Louis XVI and his wife, Marie Antoinette, would be beheaded during the “Reign of Terror” in 1793." 
The Victorian era saw a boom in the manufacture and sale of egg cups, and they've never looked back. 
There's even a word for the practice of collecting egg cups: pocillovy. It comes from the Latin term pocillum ovi, which translates to "small cup for an egg."

There are three main types of egg cups and several sub-types. A single cup is the most common type and the type most commonly collected. These are either like a little cup, with a foot or pedestal that they stand on, or what's called a bucket single, which is flat on the bottom.
The second type of egg cup is the double or "American" cup since this type was more widely used in America. A double cup has a small cup on one end, which is used like a single cup, as well as a large cup when you turn it over. The larger cup may be used for dipping toast in soft-boiled eggs or even for a poached egg.
The third type of egg cup, also more often seen in America, is the type that is similar to a custard cup. These frequently appeared during the early 20th century, and some people like to collect them. They were often made by hotels, railway lines and branches of the military and carry the markings of these.

When they are displayed, they will always spark comments and compliments, as they are such an unusual and attractive collection.

Type                             Egg cup
Material                        Bone China                      
Egg cups                      6.5 x 4.8 cm (2"55 x 1"88 inches)