The following are known Action Replay Codes for Crash Bandicoot 3: Warped on Sony Playstation (PS1).

The codes should work with the region specified but may work for other regions as well.

Device Compatibility: Action Replay, CodeBreaker & GameShark

Have All Crystals
800692DC FFFF
800692DE 08FF

Have All Gems
80069114 00F8
800692DC FFFF
800692DE 08FF
80069364 FFFF

Open All Levels
80069114 00F8
800692DC FFFF
800692DE 08FF
80069364 FFFF

Have All Powers
80069328 003F

Have All Saphires
80069364 FFFF
80069366 0FFF

Infinite Lives
D006EFEE 0000
80069108 6300
800B5EF8 6300