At a graphic level, current games are much more attractive than those of years ago, also in terms of stories, soundtrack, etc., but it must be admitted that there are certain titles that are always interesting to play again. This is why emulators continue to be so attractive. If you were looking for one in particular, here is the complete list. All emulators that exist.
Emulators to play what you want

Emulators are already commonplace and well-known among many of us, although there are still some trouble spots around them. Are they really legal? Let’s do a brief review to clarify the issue.
Emulators are legal, this is something that is not already discussed or should be discussed. On more than one occasion, it has already been supported that this type of software does not break the law. What may be the use of the BIOS / Firmware necessary to run the rest of the applications or games on a system.
It is somewhat complex, because for some emulation is the only way to access games that are no longer for sale and whose machines where they were running are also not easy to find and that they work perfectly. But hey, leaving the justification of each to use or not this option, the truth is that it could be said that if those ROMs, BIOS or Firmware were released there will be no problem in using them.

There would also be no legal issues if you managed to recreate the operation through reverse engineering, but if it was extracted using brute force techniques then you will have to have the original system to be able to use the emulation. The same happens with games (ROM). If the copyright has expired or been released, you can freely download and use it. But if not, you won’t be able to emulate them again.
So, in summary, emulation is legal as long as current copyright is respected . If the creator of the system, game or application have given their consent or the copyright rights have already been null and void, you can use them.
And now, if you like, these are all the emulators that exist today. Some allow you to enjoy the experience proposed by the first consoles or even other systems such as recreational ones or some of the curiosities that did not reach your city, such as Virtual Boy.
All Nintendo emulators

Nintendo is very clear on the subject of emulation: none of its systems and games can be emulated . Or almost, the only legal way to do it is through your virtual console. A proposal that, for example, is available on your Nintendo Switch. Although you can also play classic games on their NES and SNES consoles through the proposals for mini consoles launched in recent years.
However, none of this has prevented the existence of a multitude of emulators for its platforms for years. From the NES to the current Nintendo Switch it has emulators. Those yes, the performance between each other varies, because the power of both systems is different and the measures to avoid it too.
With a very complete catalog, the NES and SNES with the most titles accumulate within that select club of games that marked the video game industry, from the different Marios to the most valued RPGs in history.
Nintendo Entertainment System NES

- NES emulators for Windows: Jnes , VirtuaNES , Nestopia , My NES , FCEUX , RetroArch
- NES emulators for macOS: Nestopia , OpenEmu , RockNES
- NES emulators for Linux: Mednafen , RockNES
- NES emulators for Android: RetroArch , Nostalgia.NES , Nesoid
Super Nintendo SNES

- SNES emulators for Windows: RetroArch , bsnes , Bizhawk , Snes9x
- SNES emulators for macOS: RetroArch , OpenEmu
- SNES emulator for Linux: bsnes
- SNES emulators for Android: RetroArch , Snes9x EX
GameBoy

- GameBoy emulators for Windows: BGB , GB Enhanced + , RetroArch , Mednafen
- GameBoy emulator for macOS: OpenEmu
- GameBoy emulator for Linux: Mednafen
- GameBoy emulators for Android: RetroArch , My OldBoy!
GameBoy Color

- GameBoy Color emulators for Windows: BGB , GB Enhanced + , RetroArch , Mednafen , Dual TGB
- GameBoy Color emulator for macOS: OpenEmu
- GameBoy Color Emulator for Linux: Mednafen
- GameBoy Color emulators for Android: RetroArch , My OldBoy! , BGCoid
GameBoy Advance

- GameBoy Advance emulators for Windows: mGBA , NO $ GBA , GB Enhanced + , RetroArch , Mednafen ,
- GameBoy Advance emulators for macOS: OpenEmu , mGBA , VBA-M , Boycott Advance
- GameBoy Advance emulators for Android: GameBoid , John GBA
Nintendo DS

- Nintendo DS emulators for Windows: DeSmuME , NO $ GBA , RetroArch
- Nintendo DS emulators for macOS: DeSmuME , OpenEmu
- Nintendo DS emulator for Linux: iDeaS
- Nintendo DS emulators for Android: DraStic , RetroArch
Nintendo 3DS

- Nintendo 3DS emulators: Citra (Windows, macOS and Linux)
Nintendo Wii

- Nintendo Game Cube: Dolphin emulators (Windows, macOS and Linux)
Nintendo Switch

- Nintendo Switch emulator: Yuzu (Windows and Linux)
game Cube

Nintendo 64

- Nintendo 64 emulators for Windows: Project64 , Mupen64Plus , 1964 , RetroArch
- Nintendo 64 emulators for macOS: Mupen64Plus , OpenEmu , Sixtyforce
- Nintendo 64 emulator for Linux: Mupen64Plus
- Nintendo 64 Emulators for Android: RetroArch , Mupen64Plus
All Sega emulators

The Sega Master System did not reach the catalog of its great rival in those years, the Nintendo NES, but still there are interesting titles like Alex Kidd. Although the best ones came with the Megadrive and Sega Saturn. For the first there are very good role-playing games if you like the genre, in addition to the inexhaustible Sonic.
Sega Master System

- Sega Master System emulators for Windows: Mednafen , Kega Fusion , Regen , RetroArch , Higan
- Sega Master System emulators for macOS: Kega Fusion , OpenEmu
- Sega Master System emulator for Linux: Mednafen
- Sega Master System Emulator for Android: RetroArch
Sega Megadrive

- Sega Megadrive emulators for Windows: Mednafen , Kega Fusion , Regen , RetroArch , Higan
- Sega Megadrive emulators for macOS: Kega , OpenEmu
- Sega Megadrive emulator for Linux: Mednafen
- Sega Megadrive emulators for Android: Gensoid, RetroArch
Sega Game Gear

- Sega Game Gear emulators for Windows: Mednafen , Kega Fusion , Regen , RetroArch , Higan , Retrix
- Sega Game Gear emulators for macOS: Kega Fusion , OpenEmu
- Sega Game Gear emulator for Linux: Mednafen
- Sega Game Gear Emulator for Android: RetroArch
Sega saturn

- Sega Dreamcast emulators for Windows: uoYabuse , Mednafen , SSF , RetroArch
- Sega Dreamcast emulator for macOS: OpenEmu
- Sega Dreamcast emulators for Linux: Redream , nullDC , uoYabuse
- Sega Dreamcast emulators for Android: RetroArch , uoYabuse
Sega Dreamcast

- Sega Dreamcast emulators for Windows: Chankast , Redream , DEmul , nullDC , Dreamemu , RetroArch
- Sega Dreamcast emulator for macOS: Redream
- Sega Dreamcast emulators for Linux: Redream , nullDC
- Sega Dreamcast Emulators for Android: RetroArch , Reicast
All Sony emulators

The first three Playstation have also managed to emulate (PS1, PS2 and PS3) and also the Sony PSP laptop. There are many games that have been reissued and being newer consoles it is not so difficult to find models that are still 100% functional on the second-hand market.
Sony Playstation PSX

- PSX emulators for Windows: ePSXe , pSX , RetroArch , Mednafen
- PSX emulators for macOS: OpenEmu , Pcsx
- PSX emulators for Linux: ePSXe , Pcsx , Mednafen
- PSX emulators for Android: FPse , PSX4Droid , RetroArch
Sony playstation 2

- PS2 emulators: PCSX2 (Windows, Linux and macOS)
Sony playstation 3

- PS3 emulators: RPCS3 (Windows and Linux)
Sony PSP

- PSP emulators for Windows: PPSSPP , RetroArch , JPCSP
- PSP emulators for macOS: OpenEmu , JPCSP
- PSP emulator for Linux: JPCSP
- PSP emulators for Android: PPSSPP , RetroArch
All Microsoft emulators

For Microsoft consoles, only the Xbox Classic and Xbox 360 offer emulation. At least, an option to emulate some games efficiently. Because many titles are still incompatible with development and do not run. If you want to test, because your console has stopped working, here are some options.
Microsoft Xbox 360 and Xbox Classic

- Xbox 360 emulators for Windows: Xenia , CXBX , DXBX
- Xbox 360 Emulator for Android: Xbox360 Emulator Project
Other emulators that might interest you

These you have seen above are some of the most interesting emulators for the most attractive gaming platforms, although there are many more options. If you want to go back even further in time, you can find emulators of systems such as Apple AII, Atari ST, TurboGrafx and, of course, platforms such as arcade games or Neo Geo consoles.
Some emulators you could try for what they’ve meant to the entertainment industry in one way or another:
- Virtual Boy : RetroArch and Mednafen (available for Windows, Android, Linux), OpenEmu (macOS)
- TurboGrafx 16 : RetroArch (Windows and Android), OpenEmu (macOS), Mednafen (Linux)
- Neo Geo Pocke t: RetroArch and Mednafen (Linux, Windows and Android), OpenEmu (macOS)
- Atari Lynx : RetroArch (Windows and Android), OpenEmu (macOS), Mednafen (Linux)
- Amiga : WinFellow (Windows), FS-UAE (Windows. Linux and Mac)
- Commodore 64 : VICE (Windows and macOS)
And logically, the emulator that could not miss, the MAME . This is also available for various platforms:
- MAME emulators for Windows: RetroArch and MAME
- MAME emulators for macOS: MAME , SDL MAME and OpenEmu
- MAME emulators for Linux: GMAMEUI
- MAME emulators for Android: RetroArch and imama4all
As you may have already observed, both OpenEmu and RetroArch and Mednafen are like small “suites” capable of supporting various systems. So, if the systems you want to emulate are supported, the ideal is to use them and avoid having multiple apps for something you could do from a single one.
So you know, for leisure options it will not be. And do not forget to do with a good controller to play and that with distributions like RetroPie for Raspberry Pi you can also enjoy the emulation. Even have your mini console with these amazing cases.