Any unreleased song that did not make to the final version.
The final Atsushi Shindo song had graphical data before it was finally scrapped. It should be noted that Eros' data is still on the arcades, as of pop'n music Sunny Park.
The final planned licensed song for pop'n music 18 せんごく列伝. Another song by 相対性理論, ミス・パラレルワールド, was used in the next arcade release.
ryu☆オリジナル & パワーオブネイチャー（仮Edit
These songs were referenced on earlier builds of pop'n music Sunny Park. None of them were reused later, and very little information is known about them, other than they were songs by Ryu☆ and Power Of Nature, respectively.
MASS YOSHITAKA 新曲Edit
A collaboration song between DJ Mass MAD Izm* and DJ YOSHITAKA. However, it never left its dummy data state, and it was replaced by Zirkfied. The dummy data for it still remains on the final build of pop'n music Sunny Park.
Graphics for it were present when pop'n music Sunny Park was released, however its charts (and sound data) were never available. This data was later replaced in further builds.