National Pokedex:
To get the National Pokedex, defeat the Elite Four, then go to the S.S. Aqua ship in Olivine City.
Trainer Card colors:
Unlock the following Training Card colors by earning the corresponding numbers of stars. You can earn stars by defeating the Elite Four, finding all Shining Leaves, and capturing all 493 Pokemon.
Blue Card – Earn one star.
Bronze Card – Earn two stars.
Silver Card – Earn three stars.
Gold Card – Earn four stars.
Black Card – Earn five stars.
Secret box wallpapers and Pokemon eggs:
To unlock secret box wallpapers and Pokemon eggs, go to Violet City Pokemon Center. Tell the man next to the PC certain words when he asks you for your opinion. Use this website to generate these words.