cvs-fast-export analyzes a collection of RCS files in a CVS repository (or outside of one) and, when possible, emits an equivalent history in the form of a fast-import stream. Not all possible histories can be rendered this way, and the program tries to emit useful warnings when it can't. The program can also produce a visualization of the resulting commit DAG in the DOT format handled by the graphviz suite.
documentr is a Web-based tool for editing and presenting software documentation. It allows you to easily maintain documentation for multiple products and product branches. Edits can easily be copied between branches, with merge conflicts being handled gracefully. It uses Markdown as its markup language, along with some extensions, and has a role-based permission system.
git-flow Python Edition is a a pure Python implementation of git-flow. All sub-commands share a common back-end to ensure features behave the same, whatever branch-type they are working on. New workflow behavior can also be added easily by simply sub-classing existing ones. It also includes a comprehensive unit test suite, decent man pages, and HTML docs.
git-info-bar is a ksh, bash, gitbash, and Git shell plugin that endeavors to provide a fast and pronounced view of various git attributes when you are under the umbrella of a git repository. Its main feature, the 'info bar' (information bar), displays the following information: current branch (in 'red' if on master); current cksum (in 'red' if there are uncommitted changes, and an 'uncommitted changes' message in the message area); and stash count in the message area if you have stashes. It includes an install script and removal scripts. It is currently only tested in Bash, GitBash and ksh93. It was previously named 'bash-git', but the name has been transitioned to 'git-info-bar', as a long-term goal is cross-shell compatibility using a Perl back-end.
gitg targets cases where it is useful to provide a graphical representation of Git data or actions. The history view is a good example, where graphical representation helps to get an overview of the repository. gitg does not aim to be an advanced tool that allows access to every feature of Git through a graphical interface. However, it will try to incorporate common actions that might require multiple actions on the command line (like staging, unstaging, reverting, and committing).
gitolite is an access control layer on top of git. It allows you to setup git hosting on a central server, and have multiple "virtual" users (i.e., not "Unix" users) access multiple git repositories, with fine grained access control (read control at the repo level granularity, write control at branch/tag/file/dir level). It has several other features, comprehensive documentation, does not require root permissions, and does not depend on anything except git, Perl 5.8 or later, and any POSIX shell.