Ignition (gaming OS) is described as 'A fully customizable "console" in your living room that not only plays all the classic games you grew up with, but also brings modern features such as Gaming Achievements, Gaming Profiles, Online play, Social Interaction and more?' and is an app in the Gaming Software category. There are four alternatives to Ignition (gaming OS) for a variety of platforms, including Linux, Raspberry Pi, Odroid, Windows and Mac. The best alternative is Lakka, which is both free and Open Source. Other great apps like Ignition (gaming OS) are Retropie (Free, Open Source), Recalbox (Free, Open Source) and Batocera.linux (Free, Open Source).
RetroPie allows you to turn your Raspberry Pi or PC into a retro-gaming machine. It builds upon Raspbian, EmulationStation, RetroArch and many other projects to enable you to play your favourite classic games with the minimum set-up.
batocera.linux is an operating system (like Windows 10 and Mac OS) specialized in retrogaming available for your pc and different nano computers like the Raspberry and the Odroids. Note that you must own games you play in order to respect legality.