Agar
Agar GUI
20 Alternatives To Agar
Avalonia
A multi-platform .NET UI framework
BeeWare
Write your apps in Python and release them on iOS, Android, Windows, MacOS, Linux, Web, and tvOS…
Blender
Blender is the open source, cross platform suite of tools for 3D creation.
Chromely
Chromely is a lightweight alternative to Electron.NET, Electron for .NET/.NET Core developers.
Electron
Build cross platform desktop apps with web technologies
FLTK
Fast Light Toolkit - Fast Light Toolkit (FLTK)
Flutter by Google
Build beautiful native apps in record time í ½íº
Fox toolkit
fox-toolkit.org
GTK
GTK+ is a multi-platform toolkit for creating graphical user interfaces.
JUCE
JUCE is a wide-ranging C++ class library for building rich cross-platform applications and plugins…
JavaFX
JavaFX is the next step in the evolution of Java as a rich client platform.
Material-UI
A CSS Framework and a Set of React Components that Implement Google’s Material Design
Nana C Library
Nana C++ Library - a modern C++ GUI library
PortAudio
PortAudio is a cross platform, open-source, audio I/O library.
PySide
Qt for Python - Qt Wiki
Qt
C++
Qt Creator
Qt Creator is a cross-platform C++, JavaScript and QML integrated development environment. It is the fastest, easiest and most fun experience a C++ developer could wish for.
chaquopy
Python SDK for Android
wxSVG
wxSVG is C++ library to create, manipulate and render SVG files.
wxWidgets
wxWidgets: Cross-Platform GUI Library