A goldmine for digital preservation. Searching for "iOS 7 IPA Collection" often yields massive dumps of decrypted apps uploaded by enthusiasts.
Public torrents are filled with malware. Private trackers like BrokenStones (music/software) or PixelCove (legacy games) have curated collections. Search for "iOS 7 Complete Cracked IPA Set." Be prepared to maintain a ratio. ios 7 ipa archive