Snapchat - Real-time picture chatting
Rich Kids - Photo sharing app where users pay $1000/mo to share
Element.io - Secure messaging app with strong end-to-end encryption, advanced group chat privacy settings, secure video calls for teams, encrypted communication using Matrix open network. Riot.im is now Element.
Whitespaces+ - Boost your typography accuracy with a quick copy paste
StealthChat - StealthChat is Encrypted, Private, Secure Calls and Chats on Android and Apple iOS
Photo Map - High performance Android app to keep track of your photos on the map.