RWMA (Ruby window manager addons) is a modular wrapper around dmenu and dzen for adding various keyboard driven actions to (usually minimalistic) window managers, inspired by ruby-wmii. Its main purpose is launching programs and displaying notifications, but it can be expanded with plugins (for example translation, music player control, and volume control).
rxvt-unicode is a clone of the well known terminal emulator rxvt, modified to store text in Unicode and to use locale-correct input and output. It also supports mixing multiple fonts at the same time, including Xft fonts, real transparency, and an optional embedded Perl interpreter that allows you to extend your terminal easily.
s6-dns is a small, efficient, complete, and IPv6-ready DNS client library, with synchronous as well as asynchronous APIs. It is designed to replace libresolv in projects that need to perform DNS resolution. It also comes with small command-line utilities to make common and not so common DNS queries.
s6-networking is a collection of small Unix tools designed to help networking. It includes clock synchronization, Unix and TCP super-servers, Unix and TCP access control, and other miscellaneous utilities. It is particularly suited for management of clients and servers on embedded devices, but works just as well on larger systems.
sK1 is a vector graphics editor similar to CorelDRAW, Adobe Illustrator, or Freehand. it is oriented for PostScript processing. It features CMYK colorspace support, CMYK support in Postscript, a Cairo-based engine, color management, a universal CorelDRAW (CDR/CDT/CDRX/CMX/CCX) importer, an importer for Postscript, Encapsulated Postscript, and Adobe Illustrator (PS/EPS/AI), and a modern Ttk-based (former Tile widgets) user interface.