NASA Exoplanet Posters - Imagine visiting worlds outside our solar system
AnySoftKeyboard - Android (f/w 1.5+) on-screen keyboard for multiple languages.
Spacetime - Work hour and time zone management for distributed teams.
Gboard - Google-powered keyboard with search, GIFs, emojis and more!
NASA Image and Video Library - Official NASA library, searchable by keywords and metadata
Hacker's Keyboard - Are you missing the key layout you're used to from your computer when using an Android device?