App Distribution Sites

I have found these services that support mobile app distribution. I have only used TestFlight so far because it is the only free service.

Apps
I am looking for another free service like TestFlight that supports other platforms besides iOS and Android. I would also like to distribute private Tizen apps but have not found a free distribution site yet.

I will continue to list more app distribution sites here. If you have any suggestions, please let me know.