NHL Breakaway 98
Small Player
On the "Create Player" screen, type in the name "Simon Carbone." The player will be smaller and all abilities will be maximized.
Credit Goes To: Tim Kennedy via IGN 64

Secret Players
Enter the following names as shown:
grEEn jeLLo
Tommy Carbone
Simon Carbone
Olivia Carbone
Joe Seeders
Todd Dowd
 Small Player
 Secret Players
 Extra Team
 Perfect Players
 100 Bonus Points
 Cheat Menu
 Opponent w/o Goalie
Extra Teams
Here's a cool code to get some weird new teams for NHL Breakaway. When you are selecting your team press Up-C, L, Left-C. You should hear a slap-shot sound. Now between the Controller Pak and Anaheim teams you will have three extra teams.

Perfect Player(Jim Jung Code)
To create a perfect player you should first open the "Create A Player" option. Then enter the name as "Jim Jung". From there you should be able to change the other features such as name, weight, size, etc... while still having a perfect player.

100 Bonus Points
This code will add 100 bonus points to your team in the Season mode. At the main season menu, press C left, C left, C right, C right, C left, C left, C right, C right, then the R button. This will add 100 bonus points, and can be done over and over again. Helps a lot if you don't wanna wait for prospects, coaching staff, injury therapies and team events.

Cheat Menu(all cheats)
From the title screen: left C, right C, left C, right C, R, R. Now go to he main menu and the cheat screen should be selectable.

Opponent Without Goalie
Here's a cool glitch: After you start playing, go to Game Settings (press start), then go to Controller Select, and change to the other team. Under Team Options, select pull goalie. Then change the controller again back to your original team. Now there is no goalie to stand in your way.
Credit For All Codes Goes To: IGN 64