The Lanzer Doll, released in May 2009, was the first doll that was able to be held. While Gaia-tan, released March 2010, was the second doll.
Some dolls have variants in different CIs with a new look and new bonus items.
The doll called Sol (released in the Midsummer Swirl CI) originally had the number #166, but it was later changed to #106 after the Ginoverseer was released with the same number, this happened even though Sol was released first and held the number for several months. This wasn't the first time a duplicate number appeared for a doll and was quickly reassigned.