Adobe Flash Player Substitute?

Is there such a thing as a substitute for Adobe Flash Player? I access some research sites that still use Adobe flash player to open pdf's. My browsers - Safari and Firefox - would prompt me to allow flash player to activate and then the files would open. Suddenly, on Jan. 12, flash player will not work anymore and I cannot open the files - they appear to be pdf's, but open with flash player. The website is an archdiocese, They say they are working on a solution. But, it seems like there would be some substotute avialable. So many websites still use flash player. Is there a substitute plug-in? I have found some stand alone media players, such as File Viewer and Elmedia, but can find nothing that plugs into my browser. And, cannot find a way to click and drag these files - which look like pdf's - to a stand alone media player. Hope someone has a suggestion.

Tom