Yes I use those apps (ghost commander you are talking about) as well as k9mail, osmand and about 10 more. Actually I've stopped using Google Play altogether. The problem I have is that many open source apps are getting released all the time and a lot of them dont get into f-droid , for various reasons, the main one being there is not enough developers to put together the recipes. You can suggest an app on the f-droid forums but you might have to wait a while until a developer gets around to collecting the metadata, inspecting the source code for dodgy bits, and merging it. This post http://f-droid.org/forums/topic/addi...-git/#post-587
explains the process and it doesn't look that hard. I think if more developers were aware of its existence and submitted their own apps the repo would be a lot healthier.