Several large-scale studies aim to build comprehensive catalogs of all the variants in a population, for example all the frequent variants in a species or all the variants in a group of individuals with a specific trait or disease. Such catalogs are the substrate for subsequent genome-wide association studies that aim to correlate variants to traits, and ultimately to personalized treatments. Such catalogs can also be leveraged for making basic analysis tasks, such as read alignment, using not just one reference genome but a pangenome data structure representing all genomes in the catalogue. The chapter gives an overview of different pangenome data structures and their applications. Selected data structures are covered in more depth, including the r-index.