Long story short, I started a search on EyeToy Play for the PlayStation 2 (I was doing a general research on characters possible for a PlayStation crossover), ended up on the Genkivideogames website (since they had a picture of the Japanese cover art of EyeToy Play) and after discovering an option to search by Publisher, I decided to cross reference my own Master List with their Sony published titles.
I came across two more titles that went under my radar, one published by SCEI and the other published by Sony Music Entertainment. Before verifying these, I’d actually known of both titles, but in the case of one of those games, I didn’t realize it had any relation to Sony (apart from simply appearing on one of their consoles).
Wonder Trek (Jp: ワンダートレック )
Publisher: Sony Computer Entertainment Inc.
Developer: Zest Works
Release: 10 December 1998
The Youtube Channel, Import Gaming FTW, has a good video explaining what the Japan-only PS1 title is all about.
Dam Dam Stompland
Publisher: Sony Music Entertainment Inc.
Developer: Atelier Double
Release: December 4, 1997