One non free option is git-eye.

From: Anand Moon
Sent: 17-07-2013 00:08
To: Kernelnewbies@kernelnewbies.org
Subject: Git gui tools for linux

Hi All,
 
 
Could you suggest me good Git GUI tool in Linux to create/merge/update.
 
I have installed few of them like git-gui and git-cola, but I need it with some more advance option.
 
-Anand Moon