CodeBoard is an open‑source Android keyboard tailored for coding. It consolidates symbols, code navigation, editing shortcuts, and clipboard tools into one keyboard—eliminating constant layout switching between alphabets, numbers, and symbols.
Japanese hiragana keyboard for Android. It' shaped like a circle and you write by swiping towards choices. It's fast but it's not a complete Japanese keyboard. More of a proof of concept. Also a good example code if you want to make your own unconventional keyboard for Android.