FunKeys

This free keyboard adds ten new fonts that can be used in any messaging app:
✔ Round
✔ Full width
✔ Cyrillic
✔ Circles
✔ Squares
✔ Greek (premium only)
✔ Black circles (premium only)
✔ Black squares (premium only)
✔ Stroked (premium only)
✔ Small Caps (premium only)

Funkeys is designed to work together with your favorite keyboard; after using it, your favorite keyboard will be selected automatically.

To select a different mode, long press the space key.