There are no publicly documented Action Replay codes for Zubo (Nintendo DS). The game (released 2008, EU-only mostly) is obscure, uses a unique rhythm-based battle system, and was never a high-priority target for cheat databases like CodeJunkies or GBAtemp.
Use a modern emulator (melonDS, DeSmuME) with built-in cheat search:
Bottom Line: Zubo is short (~15 hrs) and designed to be beaten without cheats. Enjoy the unique soundtrack and art style instead!