UEFA Dream Soccer Unlock stadiums 1, 2, 5, and 11
At the arcade mode menu, press B, Up, Y, Left, A, Right, Down.
Unlock stadiums 3, 7, 10, and 15
At the arcade mode menu, press B, A, Left(2), Start, B, A, Left(2), Start.
Unlock stadiums 8, 13, and 16
At the arcade mode menu, press B, A, Right, Start, B, A, Right, Start.
All-Star teams
At the arcade mode menu, press Start, A, Y, Up, Right, B, A, Down.
Silicon Dream teams
At the arcade mode menu, press Y, A, B(2), A, Down, A, B(2), A, Down, Up.
Small players
At the arcade mode menu, press Down, Up, Left(2), A, Right, Down, Start.
The image featured at the top of this post is ©The Legend of Heroes: Trails of Cold Steel III key art / Original