WompMobile - WompMobile offers tow kind of functions – first creating new mobile apps and secondly converting the websites into mobile applications.
Qt - Powerful, flexible and easy to use, Qt will help you not only meet your tight deadline, but also reduce the maintainable code by an astonishing percentage.
AppGyver Composer - Visual enterprise-grade low code mobile app builder
JUCE - JUCE is a wide-ranging C++ class library for building rich cross-platform applications and plugins...
Mendix - Mendix is the fastest and easiest low-code platform used by businesses to create and continuously improve mobile and web apps at scale.
FLTK - Fast Light Toolkit - Fast Light Toolkit (FLTK)