This is one of my favorite keyboard type is Xperia Z3. Simple but it looks professional keyboard type you feel like using Mac apple keyboard. Despite of it simple and easy to use with moderate size of letters that can easy to touch and type a word you want. You can change skin and background too. Now I will teach how to install in your phone. I'm using it in my SKK LYNX running in kitkat, I don't know if can works in any android version. You must try it but at your own risk.
Requirements:
Rooted
Custom Recovery(CWM,CTR,TWRP,PHILZ TOUCH)
Phone
Z3_keyboard.zip
Procedure:
1. Download Z3_keyboard.zip and put in your sdcard.
2. Go to Recovery mode. You can use any custom recovery to flash.
3. Mount system and mount data
4. Go to Install via zip. Search in your sdcard Z3_keyboard.zip.
5. Then Reboot!
Credits:
Xperia
XDA