The following are known Action Replay Codes for Q*Bert (Game Boy) on Nintendo Game Boy / Color (GB / GBC). These codes were also known as GameShark Codes and in most cases will work on both devices.

Device Compatibility: Action Replay & GameShark

Beat The Game In Arcade Mode
91138dcd
911319c4

Max Score
9199becd
9199bdcd
9199bccd

Infinite Lives
91088bcd