mtag is the command-line tool for media files tagging. It can use the text file template to tag the multiply sets of media files. You can apply the same template for Ogg, MP3, and FLAC album versions.
Picard is a cross-platform music tagger written in Python. It supports all common audio formats (MP3, FLAC, OGG, M4A, WMA). And uses AcoustID audio fingerprints, for automatic music identification; or look up CD images even. For additional features, a wide list of plugins is available; and it's easy to extend.
adx is a minimalistic but full-featured address book for contact management running completely in web browser. Features: XML based, small (<200KB), lightweight, portable, contact tagging, geo mapping, web accounts, etc. Export functionality: vCard download, QR code generator (offline) for (vCard, WiFi, free text), Embedded Microformats (hCard 1.0, XFN). How it works: XML + XSLT = HTML web app in your web browser. Can be hosted online or local (disk, USB flash drive, etc). Own your data!