aee is a text editor that is intended to be usable with little or no instruction. It provides both a terminal (curses based) interface and native X-Windows interface (in which case the executable is called xae). Features include pop-up menus, journalling (to recover from system crash or loss of connection), cut-and-paste, multiple buffers (associated with files or not), and much more.
GNU Aspell is a spell checker designed to eventually replace Ispell. It can either be used as a library or as an independent spell checker. Its main feature is that it does a superior job of suggesting possible replacements for a misspelled word than just about any other spell checker out there for the English language. Unlike Ispell, Aspell can also easily check documents in UTF-8 without having to use a special dictionary. Aspell will also do its best to respect the current locale setting. Other advantages over Ispell include support for using multiple dictionaries at once and intelligently handling personal dictionaries when more than one Aspell process is open at once.
Beaver is an Early AdVanced EditoR, for Linux and other Unices (and even Windows); in other words, it's a text editor that is intended to be light-weight, but full of useful features for programming, from editing of web sites to C coding. It is based upon the GTK+ toolkit, supports many languages, and offers functions such as automatic indentation and syntax highlighting.
Bibcursed is a simple curses-based editor for BibTeX bibliography files, especially useful for those who have to maintain a large number of references for a major piece of documentation, like a PhD thesis. It performs everyday functions such as adding, removing and viewing reference entries. Intelligent prompting for fields is used when adding entries so that authors do not have to rely on memory for knowing which fields can and cannot be used for different entry types.
Bluefish is a programmer's Web development editor written using GTK, designed to save the experienced webmaster some keystrokes. It features a multiple file editor, multiple toolbars, custom menus, image and thumbnail dialogs, open from the Web, CSS dialogs, PHP, HTML, Java, C, and XML support, external program integration (tidy, weblint, make, javac), and lots of wizards.
Boxes is a text filter that can draw any kind of box around its input text. Box design choices range from simple boxes to complex ASCII art. A box can also be removed and repaired, even if it has been badly damaged by editing of the text inside. Since the generated boxes may be open on any side, the program can also be used to create regional comments in any programming language. New box designs of all sorts can easily be added and shared by appending to a free format configuration file. In addition to being a command line tool, Boxes integrates well with any text editor that supports filters.