"VOCALO APPEND feat. 初音ミク" is a compilation album by FARM RECORDS. Hence the title's name, it contains 18 tracks sung mainly by the Vocaloids that received append or V3 updates: Miku, Len, Rin, and GUMI. The album also features Luka, Yuki, and KAITO.
The official album website is available here.
The album is purchasable on Amazon.