Key features of i3 are correct implementation of Xinerama (workspaces are
assigned to virtual screens, i3 does the right thing when attaching new monitors), XrandR support (not done yet), horizontal and vertical columns (think of a table) in tiling. Also, special focus is on writing clean, readable and well documented code. i3 uses xcb for asynchronous communication with X11, and has several measures to be very fast....

Uzbl is a free and open source minimalist web browser designed for simplicity and adherence to the Unix philosophy. Development started in early 2009. The core component of uzbl is developed in C but other languages are also used, most notably Python. All parts of the uzbl project are released as free software under the GNU GPL version 3....

WeeChat (Wee Enhanced Environment for Chat) is a fast and light chat client for many operating systems.
Everything can be done with a keyboard, it is customizable and extensible with scripts.
It is compliant with RFCs 1459, 2810, 2811, 2812, 2813.

FreeSWITCH is a scalable open source cross-platform telephony platform designed to route and interconnect popular communication protocols using audio, video, text or any other form of media. It was created in 2006 to fill the void left by proprietary commercial solutions. FreeSWITCH also provides a stable telephony platform on which many telephony applications can be developed using a wide range of free tools....

The Cyrus IMAP server differs from other IMAP server implementations in that it is generally intended to be run on sealed servers, where normal users are not permitted to log in. The mailbox database is stored in parts of the filesystem that are private to the Cyrus IMAP system. All user access to mail is through the IMAP, POP3, or KPOP protocols....

Seahorse is a GNOME application for managing encryption keys. It also integrates with nautilus, gedit and other places for encryption operations.

Giggle is a graphical frontend for the git directory tracker (think of gitk on GTK+)

GPSBabel converts waypoint data between about fifty file formats, including Magellan and Garmin serial, Garmin USB, Mapsource, Mapsend, Streets & Trips, Delorme, National Geographic, many PDA formats, and many others. It is endian and word-size safe, includes a GUI, and runs on a variety of operating systems. It also supports Groundspeak GPX extensions for geocaching....

Cython is an optimising static compiler for both the Python programming language and the extended Cython programming language (based on Pyrex). It makes writing C extensions for Python as easy as Python itself.

GTK+ frontend to su and sudo,