When you optimize your Deck, the game will automatically review all the cards in your Library and create a Deck using the strongest or most combo-effective Cards you own. This feature is particularly useful for beginners to build a solid foundation that can be expanded as you acquire more cards.
You also have the option to enable Autofill. With Autofill activated, any new card you receive, or any card you upgrade or research that complements your current Deck, will be automatically added.
To Optimize Your Deck:
Select "Edit Deck" from the Main Menu. Click the "Autofill" tab at the top.* Choose "Optimize Now." *This tab also allows you to set your Autofill preferences.