Low memory usage xterm replacement that supports color

Security Administrator's Integrated Network Tool

http://www.wwdsi.com/saint/

Shared lib from the samba package

http://www.samba.org/

NetBIOS Name lookup tool

http://www.samba.org/

nsupdate utility with the GSS-TSIG support

https://www.isc.org/software/bind

Samba "ftp-like" client

http://www.samba.org/

A free SMB and CIFS client and server for UNIX

http://www.samba.org/

SambaSentinel is a gtk-frontend to smbstatus with additional features

API for access to scanners, digitals camera, frame grabbers etc

http://www.sane-project.org/

Stand-Alone shell combining many common utilities

http://members.tip.net.au/~dbell/

Scan_ffs recovers lost disklabel

High-speed Dirac codec

http://www.diracvideo.org/

ANSI C version of the SciMark2 benchmark

https://math.nist.gov/scimark2/download_c.html

Build tool alternative to make

https://scons.org/

Tiny shell that only permits scp and sftp

https://github.com/scponly/scponly/wiki

Converts the output of "vidcontrol -p" to PNG

Converts the output of "vidcontrol -p" to text

Multi-screen window manager

http://www.gnu.org/software/screen/

Small and lightweight screen(1) wrapper

https://sourceforge.net/projects/screenie/

Various X related scripts

https://cgit.freedesktop.org/xorg/app/scripts

ScrnSaver extension headers

http://www.freedesktop.org/wiki/Software/xlibs

Open Document Cataloging Project

http://scrollkeeper.sourceforge.net/

Cross-platform multimedia development API

https://www.libsdl.org/

SDL graphics drawing primitives and other support functions

http://www.ferzkopp.net/Software/SDL_gfx-2.0/

Simple library to load images of various formats as SDL surfaces

https://www.libsdl.org/projects/SDL_image/

Sample multi-channel audio mixer library

https://www.libsdl.org/projects/SDL_mixer/index.html

Small sample cross-platform networking library

http://www.libsdl.org/projects/SDL_net/

SDL_Pango is the SDL API to the Pango text rendering engine of GNOME 2.x

http://sdlpango.sourceforge.net/

SDL audio library and player for some popular sound file formats

http://www.icculus.org/SDL_sound/

Library to use TrueType fonts to render text in SDL applications

https://www.libsdl.org/projects/SDL_ttf/

"Simplified" DocBook XML DTD

http://www.oasis-open.org/docbook/xml/simple/

GNOME application for managing encryption keys (PGP, SSH)

https://wiki.gnome.org/Apps/Seahorse

Search using regexes for file names and text

http://searchmonkey.sourceforge.net/

Extensive german HTML reference

http://www.selfhtml.org/

Reliable, highly configurable mail transfer agent with utilities

https://www.sendmail.org/

Perl-script to send xmpp (jabber) messages

https://sendxmpp.hostname.sk/

Serf HTTP client library

https://serf.apache.org/

Manage utmp/wtmp entries for non-init X clients

Set the keyboard using the X Keyboard Extension

https://www.freedesktop.org/Software/xorg

Set of utilities that send SCSI commands to devices

http://sg.danny.cz/sg/sg3_utils.html

Generates groff and HTML from linuxdoc and docbook SGML documents

Interoperability between desktops and collaborative environments

http://oscaf.sourceforge.net

MIME types database from the freedesktop.org project

https://www.freedesktop.org/wiki/Software/shared-mime-info/

Generic script compiler

http://www.datsi.fi.upm.es/~frosal/frosal.html

Font dumper for the X font server

https://www.x.org/

HTTP regression testing and benchmarking utility

http://www.joedog.org/JoeDog/Siege

Secure Internet Live Conferencing (SILC) network toolkit

http://www.silcnet.org/

Font engine for complex non-Roman writing systems

http://silgraphite.sourceforge.net/

simple calendar and agenda application

http://wiki.gnustep.org/index.php/SimpleAgenda.app

Small (150k), fast, perl-based IRC client

http://www.iagora.com/~espel/sirc.html