International Super Star Soccer

Cheatcodes:
International Superstar Soccer 64 contains six additional, hidden teams.
To get these extra teams, all you have to do is enter the code below:

Up, L, Up, L, Down, L, Down, L, Left, R, Right, R, Left, R, Right, R, B, A, and then hold down Z and press start.
If you did the code correctly, you'll hear the announcer say, "What an incredible comeback!" Then go to the Team Selection screen, and you'll see a seventh group of teams -- All Stars. This group includes Euro Stars A, Euro Stars B, Asian Stars, African Stars, All American Stars and World Stars.

To get "big headed" players in International Superstar Soccer 64, just enter the following code at the title screen:
Top C, Top C, Bottom C, Bottom C, Left C, Right C, Left C, Right C, B, A, and then hold down Z and press Start.
If you did the code correctly, the announcer will say "Goal!"
Then once you actually start the game, the players will all have big heads.