Gboard - Google-powered keyboard with search, GIFs, emojis and more!
AnySoftKeyboard - Android (f/w 1.5+) on-screen keyboard for multiple languages.
Typing Speed Test - A simple typing test to see how fast you can type
keyboardlayouteditor - Powerful, visual designer for designing and editing keyboard layouts.
Hacker's Keyboard - Are you missing the key layout you're used to from your computer when using an Android device?
Big Quick Keyboard - Big Quick Keyboard is an Android keyboard that mimics the layout of the desktop keyboard.