Wire for iOS (iPhone and iPad)
The official Wikipedia iOS app
DuckDuckGo Browser for iPhone and Mac
Lightweight, embedded, syncable NoSQL database engine for iOS and Mac
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
A modern cross-platform low-level graphics library
Cross-Platform C++ 2D/3D game engine
Solar2D Game Engine main repository (ex Corona SDK)
Zero Hour running natively on macOS, iPhone & iPad
Open source routing engine for OpenStreetMap
A JavaScript NES emulator
An iOS & tvOS Frontend for Multiple Emulators
Improved Quake III Arena engine
Satisfying monster shooter
Tool to build cross-platform and high-performance awesome apps
Open-source engine for Heroes of Might and Magic III
JUCE is an open-source cross-platform C++ application framework
UCI chess engine
A real-time physically based 3D rendering engine for React Native
A video player for iOS, macOs, tvOS, visionOS
A powerhouse of audio functionality for macOS, iOS, and tvOS
Java/JavaFX/Kotlin Game Library (Engine)
KorGE Game Engine. Multiplatform Kotlin Game Engine & Korlibs
A completely free, open-source, 2D game engine
Real-time physically based rendering engine for Android, iOS, and more