Since there are so many games for the N64, I only put codes for most recent games. If you are looking for codes to older games click here.
 

All-Star Baseball '99
Banjo-Kazooie
Chopper Attack
Clay Fighter 63 1/3 SC
Ken Griffey Baseball
Kobe in NBA Courtside
Mortal Kombat 4
Mystical Ninja
Quest 64