FS-UAE is an Amiga emulator for Windows, Linux and Mac OS X based on UAE/WinUAE, with a focus on emulating games.

BlueStacks is an android emulator

Android emulator with over 3.000 Android configurations.

The Versatile Commodore Emulator

An Open Source DOS emulator to run old DOS games

DOSBox Game Launcher

DOSBox-X fork of the DOSBox project.

BizHawk is a multi-system emulator written in C#.

Cross-platform graphical front-end for emulators with controller navigation

A data-heavy Emulation and Gaming front-end for Windows

RetroArch is the official reference frontend for the libretro API.

An app for managing ROMs in Steam

An open-source 3DS emulator project based on Citra.

BGB is a GameBoy emulator/debugger which runs on Windows and Wine.

A multi-platform Super Nintendo (Super Famicom) emulator that focuses on performance, features, and ease of use.

Highly experimental software to emulate Wii U applications on PC.

Cross platform GameCube, Wii, and Triforce emulator

Higan is a Nintendo multi-system emulator.

Open-source Game Boy Advance emulator.

Mupen64Plus is a cross-platform plugin-based N64 emulator which is capable of accurately playing many games.

A basic launcher for Mupen64Plus

A portable and cycle-accurate NES/Famicom emulator written in C++

N64 Emulator

SNES emulator widely ported to many systems

Game Boy, Game Boy Color, and Game Boy Advance emulator

SNES emulator written mostly in x86 low-level assembly language

Engine for classic adventure and role-playing games.

SimH (History Simulator) is a collection of simulators for historically significant or just plain interesting computer hardware and software from the past.

ZX Spectrum Emulator

An open source PS2 Emulator

A PSP emulator for Android, iOS, Windows, Mac and Linux, written in C++.

an IBM 3270 terminal emulator for Windows.