Adobe Systems has developed Flash Player 18, which has the most number of installations recorded. When installed on your system, it defines an auto-start registry entry, allowing the plug-in to run upon each boot. Moreover, it adds a background controller service to run automatically.
Most people use version 27, which is the latest version, to handle streaming and gaming content on their computers. However, there were rumors that version 18 has so far been the better version. You might not find a link to that version nowadays, since it was last shared on the Internet somewhere around in 2015.
A link was shared on Reddit though via one of its forums in the past months for Adobe Flash Player 18 that you can download. However, the problem was that when the user used this version, something went wrong. The screen of his computer just turned black. In fact, there was an error message that popped up. When the user revert the changes he had done and went back to version 26, everything went fine.
Perhaps the user was not able to follow the instructions completely, which was shared on Reddit. Sometimes it would require technical skills in order to do some tweaks on your system. Thus, it is important to make sure that you have knowledge on whatever you are doing so that problems will be avoided along the way.
Take note that Adobe Flash Player will soon be discontinued by 2020, so there is a possibility that any of these versions will no longer work. For the meantime, it is important to keep your version of the plug-in updated to its latest to take advantage of the new features not found in the older versions. You can also notice that Internet browsers and websites have already switched to HTML5, indicating that more and more users are bound to leave Flash Player anyway.