(www.ghacks.net)
One option comes in the form of preservation projects. Examples are the Flash Games Preservation Project that preserves hundreds of Gigabytes worth of Flash content, specifically games, and the Internet Archive, which makes Flash content playable in an emulator on the archive's website.
The Internet Archive uses an emulator that is called Ruffle; the emulator is written in Rust and it supports all modern operating systems and modern we browsers that support WebAssembly. What is interesting about Ruffle is that its developers have created browser extensions for Firefox, Chromium-based browsers such as Chrome, Edge, Brave, Opera, or Vivaldi, and for Safari.
Installation of Ruffle in the browser of choice adds Flash emulation to the browser. The browser detects Flash content automatically and you can play it then as if Flash would still be installed.
Today is the last day of Flash, so I'm re-sharing this on wanting to play Flash content after today. Very useful.
How to play Flash content in your browser in 2021