If you'd like to see a listing of gift cards purchased (or issued because payment was taken for them) in the POS over a period of time, you can do so by building the following report:
On the Filters tab, select the date range that you would like to report on.
On the Metrics tab, add this metric to the report: "Source Sales » Gift Cards Issued"
On the Groups tab of reporting, you can remove all groups and that will give you just the totals. If you'd like to see this reported by gift card number, you can add the "Gift Cards » Gift Card #" group to the report.
The 'Source Sales >> Gift Card Issued' Metric is a metric for Gift Cards Sold (or purchased) in the POS or via Sales Orders. It does not include Gift Cards Issued when returning product as per this article: How To Handle Store Credits in Heartland Retail The metric for Gift Cards Issued when returning product (some call it a store credit) would be 'payments > refunds' for the group 'payments > payment type' in Reporting.