I recently, read the post Choosing Mobile GIS applications for Android Tablets?
I have seen a Github repository page https://github.com/vhf/free-programming-books used for a similar purpose.
Is there a Github repository page for maintaining a list of GIS in mobile ecosystem (i.e., Android, iOS, Windows Phone, etc.)?
When I searched GitHub for Mobile GIS repositories I found 59 but none appear to be what you are after.
If you wish to commence one at GitHub, and assuming that site allows you to, then I think that would be a more suitable place to maintain it than on this Stack Exchange site which promotes focussed Q&A, closes new list questions, and locks old list questions.
I created a Github repository GIS-Geographic-Information-Systems-Mobile-Applications-list after not finding any matches to the requirement of crowdsourced GIS mobile application list through 59 search results by the user PolyGeo & my own search results in Github using keywords like mobile GIS list, others.
