DOSBox is a DOS-emulator that uses SDL-library to run old DOS-based applications and games on modern computers by emulating an IBM PC, as well as the necessary hardware around it. It also allows you to make use of virtual hard drives, mount ISOs to virtual CD-ROM drives, cast and capture your emulated display, and many other quality of life features. It all currently has all SVN changes and some more features.
DOSBox Staging is an attempt to revitalize DOSBox's development process. It's not a rewrite, but a continuation and improvement on the existing DOSBox codebase while leveraging modern development tools and practices.
For example, they want to improve the out-of-the-box experience for new users, integrate several notable community-developed patches that are not included in the SourceForge-hosted project, implement new features and quality-of-life improvements, prioritize DOS gaming while focusing on supporting up-to-date, current Operating Systems and modern hardware. For technical comparisons, please check here.
DOSBox-X is a free and cross-platform DOS emulator for running DOS games and programs. Started as a fork of the DOSBoxproject, it retains compatibility with the wide base of DOS games and DOS gaming DOSBox was designed for. But it's also a platform for running DOS applications, including emulating the environments to run Windows 3.x, 9x and ME and software written for those versions of Windows. DOSBox-X aims to be a complete DOS emulation package that is both fully-featured and easy to use, covering all pre-2000 DOS and Windows 9x based system scenarios.
While they have made efforts to maintain and improve the emulation accuracy of the hardware and many more ways to configure the DOS virtual machine, they also try to strike a balance between emulation quality, speed, and usability, including improving the out-of-the-box experience for new users who want to run DOS programs or games, as well as implementing emulation that is accurate enough to make retro-programming possible with confidence the program will run properly on actual hardware.
DS4Windows is a portable program that allows you to use a PlayStation DualShock 4 on your PC by emulating a Xbox 360 controller. This project is actually a fork of the work of Jays2Kings, which can be found on the old project website at ds4windows
JoyToKey enables PC game controllers to emulate the keyboard and mouse input, so that windows applications and web games can be controlled with your joysticks. Whenever buttons and sticks are pressed on the controllers, JoyToKey converts them into keyboard strokes and/or mouse movements so that the target application will work as if a real keyboard and a mouse were used.