There are an awful lot of GCSs out there (possibly more than anyone needs), but here's another one: CityFlyer.
I Heart Robotics explains: "The CityFlyer ground station takes different approach to developing a control system for UAVs. While other systems try to provide as much information as possible, this one seems to focus on readability. Also, since it is based on GTK+ and ROS it may be useful for other robots."
"Each of the instruments are well documented and implemented using the Cairo scalable vector graphics library, which means that each gauge could scale up to full screen without looking pixelated. Controls are also provided for a high contrast mode which might be useful for daylight readable displays. Since the individual instruments are implemented as GTK widgets they could also be used to build your own ground station.
Rumor has it that the lead developer is graduating soon and looking for work, so feel free to contact him here."