Yet another Basic for Unix and Windows

http://www.yabasic.de/

Original free open-source forum written in Perl

http://www.yabbforum.com/

Display GNOME dialogs from the command line

https://github.com/v1cont/yad

Yet another FTP client, similar to ftp(1)

https://github.com/sebastinas/yafc

Yet Another File Integrity Checker, similar to Tripwire

http://philosophysw.com/software/yafic/

Portable JSON parsing and serialization library in ANSI C

http://lloyd.github.com/yajl/

Enhanced execution box with regex pattern matching

http://offog.org/code/

Package manager for node, alternative to npm (meta port)

https://classic.yarnpkg.com/

Package manager for node, alternative to npm

https://classic.yarnpkg.com/

Package manager for node, alternative to npm

https://classic.yarnpkg.com/

Package manager for node, alternative to npm

https://classic.yarnpkg.com/

Package manager for node, alternative to npm

https://classic.yarnpkg.com/

Default GTK theme for Ubuntu

https://github.com/ubuntu/yaru

Default icon theme for Ubuntu

https://github.com/ubuntu/yaru

POSIX-compliant command line shell

https://magicant.github.io/yash/

Complete rewrite of the NASM assembler

https://yasm.tortall.net/

General-purpose console screen reader

https://yasr.sourceforge.net/

Yet Another LaTeX mode and html mode on Emacs

http://www.yatex.org/

Diff readability enhancher for color terminals

https://github.com/ymattw/ydiff

Terminal wrapper for creating drop-down consoles

http://phrat.de/yeahtools.html

Minimal X11 window manager with BeOS-like tabbed titles

http://phrat.de/

Help browser for the GNOME desktop

https://www.gnome.org/

Utilities to help manage documentation for Yelp and the web

https://wiki.gnome.org/Apps/Yelp/Tools

DocBook XSLT stylesheets for yelp

https://www.gnome.org/

Free (GPL) encoder and decoder for the yEnc Usenet file format

http://www.yencode.org/

Amateur Radio curses based logging program

https://fkurz.net/ham/yfklog.html

Yubico C client library

https://developers.yubico.com/yubico-c-client/

Library and tool for personalization of Yubico's YubiKey

https://developers.yubico.com/yubikey-personalization/

Command-line YAML and XML processor, jq wrapper for YAML/XML documents

https://kislyuk.github.io/yq/

YouTube downloader written in Go

https://github.com/rylio/ytdl

Unpack data in MS Outlook TNEF format

https://github.com/Yeraze/ytnef

Yubico PIV tool

https://developers.yubico.com/yubico-piv-tool/

Seamless ssh-agent for YubiKeys

https://filippo.io/yubikey-agent

The Yahoo! JavaScript and CSS Compressor

https://yui.github.io/yuicompressor/

Tool to decode yEnc encoded files

http://yydecode.sf.net/

Dynamically typed N-D expression system based on xtensor

https://github.com/xtensor-stack/zarray

Puzzle game where the player has to arrange balls in triplets

https://zaz.sourceforge.net/

ZBar barcode reader

http://zbar.sourceforge.net

Compressed file format that splits the file into independent chunks

https://github.com/zchunk/zchunk

Source port for Doom-engine games

https://www.zdoom.org/

Free RIPv1, RIPv2, OSPFv2, BGP4 route software (server/reflector)

http://www.zebra.org/

Event logging framework

https://wiki.gnome.org/Projects/Zeitgeist

Framework for developing PHP web applications

https://framework.zend.com/

Display GNOME dialogs from the command line

Simpler web photo gallery

https://www.zenphoto.org/

Network virtualization everywhere

https://github.com/zerotier/ZeroTierOne/

Zetaback ZFS backup and recovery management system

https://github.com/omniti-labs/zetaback/

Simple way of maintaining zfs snapshots using the periodic system

http://www.neces.com/blog/technology/integrating-freebsd-zfs-and-periodic-snapshots-and-scrubs

ZFS Snapshot Replication Script

https://github.com/aaronhurt/zfs-replicate

Tool to sieve ZFS snapshots as per given spec a la 'pdumpfs-clean'

https://github.com/knu/zfs-snapshot-clean