Card packs are reward bundles that contain multiple Collection cards. You earn them by playing events.

🃏 Each pack has its own color tied to how many cards it gives:

• Common Pack: 2 cards
• Uncommon Pack: 3 cards
• Rare Pack: 4 cards
• Ruby Pack: 6 cards with a higher chance of rarer cards
• Diamond Pack: 6 cards, with at least 1 new card

You can read more on how cards are distributed in packs here