EmuNations

Launchbox is a front-end wrapper for emulators. Not only does it automatically download box art for games, it also grabs fanart, screenshots, logos and more to create an immersive experience via BigBox.

It also supports arranging and filtering by genre, platform, ESRB rating, developer, publisher, genre, etc. It also includes automated import processes for your MS-DOS games, ROM files, and Steam in order to help get you up and running as quickly as possible. Game box-art and metadata can also be automatically downloaded from their Games Database or community-based online databases.

Steam Rom Manager is a bulk game importer and artwork manager for Steam. It's basically an app for managing ROMs and benefiting from what Steam has to provide. This includes using big picture mode, its overlay, controller management layout,  streaming options and much more..

Xbox 360 Controller Emulator allows your controller (gamepad, joystick, wheel, etc.) to function as an Xbox 360 controller. For example, it lets you play games such as "Grand Theft Auto" (GTA) or "Mafia II" using a Logitech Wheel.

WineD3D For Windows is a DirectX 1-11 to OpenGL wrapper with almost full implementation of DirectX used in Wine. Even if Windows supports DirectX natively, using WineD3D can enhance backwards compatibility with older games, especially on Windows 8+ that don't support 16-bit screen modes. Others possible values include eliminating unsupported versions of DirectX, or porting DirectX applications to OpenGL without having to rewrite the rendering code. That said, it's far from perfect... 

QEMU is an open source machine emulator and virtualizer.
When used as a machine emulator, QEMU can run OSes and programs made for one machine (e.g. an ARM board) on a different machine (e.g. your own PC). By using dynamic translation, it achieves very good performance. 

Modern fork of x360ce built with SDL3, ViGEmBus, vJoy, Windows MIDI Services, HelixToolkit, .NET 10 WPF, and Fluent Design. Turn any input device into any virtual controller:
Gamepads, joysticks, keyboards, mice, and touchscreens — mapped to Xbox 360, DualShock 4, DirectInput, MIDI, or Keyboard+Mouse output that games treat as real hardware.

dgVoodoo is a wrapper for old graphics APIs to run on modern Windows operating systems. Its applied using Direct3D11 with different types of wrapping outputs:

• Hardware rendering at GPU feature level 10.1 (recommended)

• Hardware rendering at GPU feature level 10.0 (there are some restrictions)

• Software rendering through Microsoft WARP renderer

The API's it currently can wrap are:

• Glide 2.11, Glide 2.45, Glide 3.1 and Glide 3.1 Napalm

• DirectX 1-7 (all versions of DirectDraw and Direct3D up to version 7)

• Direct3D 8.1

You also need the 3Dfx splash dlls for Glide if you want 3Dfx splash screen or watermark (shameless plug) through dgVoodoo. 

• 3DfxSplashDlls.zip

You may also need D3DRM.dll (Direct3D Retained mode) for some games and demos. It's not part of the OS since Windows Vista.

• D3DRM.zip

VirtualBox is a powerful x86 and AMD/Intel64 virtualization solution for home and enterprise usage. It's quite feature rich, high performance yet is freely available as an Open Source Software. While it's mainly a community effort, Oracle is backing it to ensure it maintains high standards of quality.

Presently, it runs on Windows, Linux, Macintosh, and Solaris hosts and supports a large number of guest operating systems including but not limited to Windows (NT 4.0+, DOS/Windows 3.x, Linux (2.4, 2.6, 3.x and 4.x), Solaris and OpenSolaris, OS/2, and OpenBSD.