One-Hand is the best keyboard to use your device with one hand, as it follows the natural curve your fingers describe over the screen you will feel really comfortable as you write.
It adapts perfectly to your screen size, and also you can choose with which hand you want to use it, also on iPad, you can choose to use both hands just like the system keyboard.
Be sure that this app does NOT collect any private data, your data is not my business so you can use this app safely.
Included keyboards: english, spanish, catalan, french, german, italian, dutch, polish, norwegian, danish