Jikkyou Powerful Pro Yakyuu '99 Codes -

Display all player stats:
Press C-Up(2), C-Down(2), C-Left, C-Right, C-Left, C-Right, Start at the status screen.

All bonus stadiums:
Press C-Up, C-Left, C-Right, C-Up, C-Right(2), Z, C-Left, C-Right, C-Left, C-Right, Start at the stadium selection screen.