The following are known Action Replay Codes for Pokemon Channel on Nintendo GameCube (GCN).

Master Code – Must Be On
X5BF-ATDY-J9PWG
B714-34F3-AU35A

Press L+R+X-Tons Of Money
HWP0-WTQR-GDF6R
1QN2-23QA-U7YXY
N9CE-MHK9-RQB1U

Press L+R+X-Have All Nice Cards
XW14-Z41V-UUZ0K
ZAGP-2XA3-E0ENB
V0N7-W918-AGPUR
RC84-RFRN-AFHZV
DFMR-455C-16DAY
RC84-RFRN-AFHZV
PMG7-MB56-J8GFY
RC84-RFRN-AFHZV
Y2AW-9NDD-QYCM1
RC84-RFRN-AFHZV
E9FZ-A3QA-YCERP