NotDeft is an Emacs-based manager and local search engine for directories of plain text notes. NotDeft features a Xapian backend for efficient free-text search over potentially very large numbers of note files; in that respect it is like the Notmuch Emacs mode for managing email. NotDeft is a spin-off of the Deft note manager, and retains similar functionality for browsing, filtering, and managing note collections. While NotDeft inherits its user interface from Deft, that interface is used for managing search result sets of notes, rather than directory contents.
I'm increasingly using NotDeft not only for note taking, but also for capturing information from various sources. To some extent it already acts as a lightweight substitute for the likes of Evernote. As explained in the documentation, Org mode's built-in capture protocol can be used to send snippets of text from a page open in a web browser into one's NotDeft note collection. Sometimes, however, we already have a URL of an interesting page in our clipboard, and we would like to fetch the entire page's textual content into NotDeft with a single command.
My NotDeft note manager has an optional notdeft-path feature to better support transient directories of notes. Also in the standard configuration, the notdeft-directories list may contain directories that do not have to always exist, as any non-existing directories are simply ignored; if and when they appear, they can be included in subsequent searches. Note, however, that the notdeft-directories variable is normally set only once, and if the initializer expression includes wildcards, the variable value may not contain directories that get mounted or copied over later.