When Nepgear uses her SP Skill Friendship, she summons a pop-up book featuring characters from various series made by the late Osamu Tezuka.

The Japanese version has an additional DLC party member named Compile. She is named after Compile Heart's precursor company, famous in Japan for creating the Puyo Puyo series.
Most likely due to licencing issues (since parts of Compile were sold to SEGA), she was never made available in the North American and European versions of Victory.

If you look closely at Noire's belt in her Neptunia V outfit, you can see 2 PlayStation memory cards as well as a PocketStation, a memory card that could interact with a small number of PlayStation games. Make Noire the party leader and getting the camera to zoom in on her belt, a cat can be seen on the PocketStation's screen, a reference to the PlayStation's mascot, Toro Inoue.

Plutia is named after an unreleased SEGA console, in this case, the SEGA Pluto, a modified SEGA Saturn with a built-in NetLink Modem. The Pluto's existence was never known until internet posts, starting in April 2013 by a former SEGA employee, showed off the very few prototypes that exist. Despite being named after the Pluto, her design is based around that of the SEGA Genesis.

One of the downloadable characters is known as CC, a character made to represent the company CyberConnect 2.

This characters design is loosely based off of a mixture of Kite's outfit, and Blackrose's tattoo's from the hit series .hack, a game created by CyberConnect 2.