You will find different discount packs for the different functions of the game such as permanent skins, partners, cards to advance a character you already have. Each pack is composed of the object and gold. 

The Red or Gold Evolution Cards:

These universal cards are essentially used to advance, power-up your partners you already have but of red or gold quality without having the card. 

Example:

When you want to increase the stars in the Akatsuki function, from the Red Quality, you can use two options: character fragments or Universal Card.

Permanent Skins

Permanent Skins are transformations that bring extra bonuses to your team.

Note that some of them have a limited duration (2 days). You can check that by clicking on the card before you buy it.