How can i see which gift certificates can still be used?

In the 'Gift card' filter under Modules > Manage gift cards, you will find an overview of the gift cards that have been created. As in all filter views, various columns can be added to the overview. For example, you can add columns such as: the product for which the gift card is valid, the date on which the gift card was used, and the customer to whom the gift card is linked.