An insert is a category of sports card found when opening packs from any given sports card product, but are separate from the base set of the product. Inserts are usually slightly more rare and can be sought after by sports card collectors because they often feature unique designs and content.
While inserts will be listed on the sports card product’s checklist alongside the base card checklist, they will be identified by a unique card numbering format. Usually if you see a card numbered with some combination of letters and numbers (eg. AH13), it can be safely assumed that it’s an insert.
Types of inserts include: autographs, memorabilia/ relic cards, special themes (such as award winners or all stars) and other short print cards.
Inserts are usually more flashy than base card designs and can come in unique shapes (die cut cards), finishes (foil designs) and colors.