legit
Legit is a complementary command-line interface for Git, optimized for workflow simplicity.
Project Source: https://github.com/kennethreitz/legit
Project Homepage: http://www.git-legit.org/

git-imerge
Incremental merge for git.
Project Source: https://github.com/mhagger/git-imerge

dulwich
Pure-Python Git implementation.
Project Source: https://github.com/jelmer/dulwich
Project Homepage: http://www.samba.org/~jelmer/dulwich/

octogit
A free and open source interface to github from the command line.
Project Source: https://github.com/myusuf3/octogit
Project Homepage: http://myusuf3.github.io/octogit/

hg-git
This is the Hg-Git plugin for Mercurial, adding the ability to push and pull to/from a Git server repository from Hg.
Project Source: https://github.com/schacon/hg-git
project Homepage: http://hg-git.github.io/

gittle
Gittle is a high-level pure-python git library.
Project Source: https://github.com/FriendCode/gittle

GitPython
GitPython is a python library used to interact with Git repositories.
Project Source: https://github.com/gitpython-developers/GitPython

git-sweep
A command-line tool that helps you clean up Git branches that have been merged into master.
Project Source: https://github.com/arc90/git-sweep

git-cola
The highly caffeinated Git GUI.
Project Source: https://github.com/git-cola/git-cola
Project Homepage: http://git-cola.github.io/

gitsome
A supercharged Git/GitHub command line interface (CLI)
Project Source: https://github.com/donnemartin/gitsome