audioloader is a minimalist music library browser that enables the browsing of a local music collection in any Web browser. It supports album/directory oriented audio/music listening. Album playlists are generated dynamically, and can either be queued into Audacious through a script distributed with the application or downloaded and opened with any music player. It is self-contained with no dependency on any external application but the Web browser, and supports cover art display, history, random album selection, and sub-collections. It has limited mobile support, as well.
mdepub is a tool that allows you to compose a book in Markdown format and use Pandoc and Calibre to compile an Epub package including all of the book's source material. In effect, you can keep the source and product in the same file in your library; if you ever want to revise the product, you merely need to extract the source, make edits, and recompile.