Hatsune Miku
Hatsune Miku was the first Vocaloid developed by Crypton Future Media after they handled the release of the Yamaha vocal Meiko and Kaito. The name of "Hatsune Miku" was conceived soon after the Vocaloid 2 announcements, when an English and Japanese vocal were developed for the character. The intended design was delayed and later used for Megurine Luka instead. Miku was intended to be the first of a series of Vocaloids called the ""Character Vocal Series"", which included Kagamine Rin/Len and Megurine Luka. Each had a particular concept and vocal direction.
Ievan Polkka
The Finnish folk song was also given popular covers by several Japanese Vocaloid singers, such as Megurine Luka, Kagamine Rin, and Kagamine Len. The most popular vocaloid cover belonged to that of Hatsune Miku, garnering more than 40 million views on her official YouTube music video as of December 2017. Its popularity has lent itself to being used in the Vocaloid rhythm game "" as the tutorial music. It has also been used in a commercial promoting the LG G5 smartphone.