The original vi editor

http://ex-vi.sourceforge.net/

IBM 3270 font for the nostalgic

https://github.com/rbanffy/3270font

The traditional 4.4BSD /bin/csh C-shell

The traditional 4.4BSD rdist

Resolution tool for Intel i915 video cards

Port of various original plan9 tools

http://tools.suckless.org/9base

Fast image processing tools based on ImageMagick

http://www.graphicsmagick.org/

Haskell code font with monospaced ligatures

https://github.com/i-tu/Hasklig

Fast pixel formats conversion library

Image processing tools

http://www.ImageMagick.org/

Image processing tools

http://www.ImageMagick.org/

Image processing tools (unstable version)

http://www.ImageMagick.org/

C++/Python lib of 2D/3D vector, matrix, math ops for computer graphics

https://github.com/AcademySoftwareFoundation/Imath/

Enhanced Printer Spooler

http://lprng.sourceforge.net/

High-performance CORBA ORB with support for the C language

Language for statistical computing and graphics

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

Unicode Character Database

http://unicode.org/ucd/

3-D Athena Widget set that looks like Motif

TrueType font server for X11

http://www.hadrons.org/software/xfstt/

Formats an ASCII file for printing on a postscript printer

http://www.inf.enst.fr/~demaille/a2ps/

An ascii art library

http://aa-project.sourceforge.net/aalib/

Open-source, cross-platform WYSIWYG word processor

http://www.abisource.com/

AbiWord help files

https://www.abisource.com/

Addressbook program with mutt mail client support

http://abook.sourceforge.net/

Abseil Common Libraries (C++)

https://abseil.io/

Interactive Python accessibility explorer for GNOME

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

D-Bus interface for user account query and manipulation

http://cgit.freedesktop.org/accountsservice/

Receive faxes using sound card and radio

Analog Clock for GNUstep

http://gap.nongnu.org/aclock/index.html

PC/SC driver for CS CCID smart card readers

https://www.acs.com.hk/en/driver/4/acr38-smart-card-reader/

Messaging and Integration Patterns provider

http://activemq.apache.org

Program for sending email messages for CVS repository commits

http://search.cpan.org/dist/activitymail/

ADAMEm is a portable Coleco ADAM and ColecoVision emulator

http://www.komkon.org/~dekogel/adamem.html

Complain about inappropriate commercial use (f.e. SPAM) of usenet/e-mail

http://www.rdrop.com/users/billmc/adcomplain.html

Versatile addressbook for GNUstep

http://gap.nongnu.org/addresses/index.html

Goodies for addressbook for GNUstep

http://giesler.biz/bjoern/en/sw_addr.html

Easy to use asynchronous-capable DNS client library and utilities

https://www.chiark.greenend.org.uk/~ian/adns/

Adobe CMap collection

http://partners.adobe.com/asn/tech/type/ftechnotes.jsp

Database library for PHP

http://adodb.sourceforge.net

Database library for PHP

http://adodb.org/

SDL MAME port with advanced TV and monitor video support

http://www.advancemame.it/

GNOME Symbolic Icons

Affiche allows people to stick notes

http://www.collaboration-world.com/cgi-bin/project/index.cgi?pid=5

Window manager originally based on the Bowman NeXTstep clone

http://www.afterstep.org/

FTP-like shell for accessing Apple II disk images

High Quality Rendering Engine for C++

http://www.antigrain.com/

Approximate grep (fast approximate pattern-matching tool)

Replacement and extension for Tripwire

https://aide.github.io/

802.11 WEP and WPA-PSK keys cracking program

http://www.aircrack-ng.org/

Collection of patience games written in guile scheme

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