Other FLOSS/Linux software directories
Freecode.com (AKA Freshmeat) was the original software release tracker, and is still available as archive.
Sourceforge.net Is the classic open source development service and still home to and primary hub for many projects.
Fossies.org tracks popular open source packages; and is quite feature-rich underneath its classic interface.
Open source security software Freshermeat instance for tracking security-oriented projects.
GitHub is a prettier frontend onto git source control. Less suited for end users, but still allows searching for software.
Ice Walkers is also a software release tracker and news blog, with its own software directory.
Repology, the packaging hub Tracks software releases/versions across distros and directories.
Open Source Software Directory Lists only stable and well-known Linux software, as it's intended for end users.
Launchpad is the development hub for Ubuntu and also lists a few things that haven't made it into the package managers yet.
OS as Alternative Lists commercial/prioprietary software and the Free or Linux alternatives in usage categories.
OpenHUB (Ohloh) statistically tracks open source project development.
Zwodnik provides a pretty overview, categorization, description and reviews for open source packages.
Linux Alternatives Curates a list of Linux software alternatives for migrating newcomers.
Savannah Provides an alternative Free software development plattform.
CoolGitHubProjects is a subreddit discussing interesting finds from (otherwise opaque) GitHub repos.
LinuxSoft.cz Provides a comprehensive and searchable software list divided into categories.
Wikipedia: List of free and open source software packages summarizes a few common names.
DistroWatch Does as it says and tracks new and upcoming BSD / Linux / GNU / Solaris distribution releases.
Linux AppFinder Provides vast categories and application options, alternative lists, web feeds, news, and a community forum.
Open Source Scripts Collects web applications and web service scripts.
Libe.net is an archive and version tracker for various Linux and open source packages.
OpenSourceList.org Collection of best-per-category software; also includes MacOS and Windowsware.
Open Source List Provides a summary list of common applications.
Open Source Arcade is an assemblage of games categorized per programming language or genre.
Libre Projects is itself a meta directory to various open source and open content directories and community hubs.
Open Font Library Helps to easily uncover new and nicely categorized true or open type fonts.
Find Best OpenSource is a well curated news and application category blog.
Free Open Source Software A Wiki which doesn't host a software directory itself, but provides various resources to uncover them.
OpenHatch enables matchmaking for projects and their developers and interested users and contributions.
the changelog Is a blog and weekly podcast on open source development and interesting projects.
AlternativeTo is an extensive meta cross-reference list of web sites and applications.
BeOpen directorizes open source projects, software forges, news, events, links and organisations.
Linux Games DB is cataloging and searching for new Linux-specific and compatible games.
Gtk-Apps lists existing and updated Gtk+/Gnome applications
openDesktop aggregates Qt/Gtk/Gnome and Java/Wine application releasess
Portable Linux Games provides pre-build and distribution independent .run packages.
TuxArena has news, application lists, and tutorials for Ubuntu, Debian, Mint.
LinuxSoftNews.WP is a blog with monthly software release summaries and detailed reviews
FOSSHUB is a project download hoster and release announcer for some well-known apps.
Free Software directory is the FSFs Wiki to summarize FLOSS packages and projects.
Linux Games Captures progress and newly released gaming software for Linux.
and its web chat
They are more software forges and hosters though:
Programming-language specific developer hubs and package repositories often allow uncovering new software as well.