A prototype build for PlayStation All-Stars Battle Royale shows an early character select screen with a set of unused characters:

•Chop Chop Master Onion from the PaRappa the Rapper series
•Captain Blasto from Blasto
•Buzz from the Buzz! series
•A Big Kulche from the LocoRoco series
•Dr. Nefarious from the Ratchet & Clank series
•A Eucadian Soldier from Warhawk
•A knight from Fat Princess
•Um Jammer Lammy from the PaRappa the Rapper series

Notably, Dr. Nefarious is featured in the roster without Ratchet or Clank. PaRappa the Rapper is the most represented series in this roster, and has more characters than any one series would get in the final game including DLC. The knight would appear in Fat Princess' moveset, LocoRoco and Buzz! would be represented through stages, and Blasto would be absent completely.