OAIster OAIster is a database of over 20 million items held digitally at nearly 1100 libraries, museums, and organizations. Types of files include digitized (i.e., scanned) books and articles; born-digital texts; audio files (e.g., wav, mp3); images (e.g., jpg, gif); movies (e.g., mp4, quicktime); and datasets (e.g., downloadable statistics files).