The following are known Action Replay Codes for Bomberman 64 on Nintendo 64 (N64).

Device Compatibility: Action Replay & GameShark

Stop Timer
802AC633 0000

Press PAR Button For 99 Gems
882AC61F 0063

Infinite Lives
802AC617 0063

Infinite Credits
802AC61B 0063

Best Bomb
802AC640 FFFF