Battletoads.

 No.  Code  Effect
   1  C3BT-AA5A  Infinite lives
   2  AABT-BA7R + ABPA-EAH6  Player 1 starts with 1 life
   3  AJBT-BA7R + AKPA-EAH6  Player 1 starts with 3 lives
   4  ATBT-BA7R + AVPA-EAH6  Player 1 starts with 5 lives
   5  BEBT-BA7R + B1PA-EAH6  Player 1 starts with 10 lives
   6  CNBT-BA7R + CPPA-EAH6  Player 1 starts with 20 lives
   7  AABT-BA7R + ABPA-EAH6 + ABPT-EABG  Both players start with 1 life
   8  AJBT-BA7R + AKPA-EAH6 + ABPT-EABG  Both players start with 3 lives
   9  ATBT-BA7R + AVPA-EAH6 + ABPT-EABG  Both players start with 5 lives
 10  BEBT-BA7R + B1PA-EAH6 + ABPT-EABG  Both players start with 10 lives  
 11  CNBT-BA7R + CPPA-EAH6 + ABPT-EABG    Both players start with 20 lives
 12  PT7T-AA54 + CKHA-AA5J  Take less damage
 13  APBT-AAD4 + AN0T-AAAL  Start with 1 energy block
 14  BPBT-AAD4 + BN0T-AAAL  Start with 3 energy blocks
 15  CPBT-AAD4 + CN0T-AAAL  Start with 5 energy blocks
WITH CODES 16 THRU 18, YOU MAY NEED TO SWITCH OFF TO GO ON.
 16  AA5T-B92Y  Extremely bogus jump
 17  AA5T-B72Y  Mildly bogus jump
 18  AA5T-B52Y  Bogus jump
CODES 19 THRU 21 DON'T WORK ON ALL LEVELS
 19  AA5T-BZ2Y  Higher jump
 20  AA5T-BV2Y  Super jump
 21  AA5T-BK2Y  Mega-jump
 22  AJZT-AAC4  Start on level 2
 23  ANZT-AAC4  Start on level 3
 24  ATZT-AAC4  Start on level 4
 25  AYZT-AAC4  Start on level 5
 26  A2ZT-AAC4  Start on level 6
 27  A6ZT-AAC4  Start on level 7
 28  BAZT-AAC4  Start on level 8
 29  BEZT-AAC4  Start on level 9
 30  BJZT-AAC4  Start on level 10
 31  BNZT-AAC4  Start on level 11
 32  BTZT-AAC4  Start on level 12
 33  BYZT-AAC4  Start on level 13