EDIT:
Here's a list of browsers that still support NPAPI from Wikipedia:

There is a special version of Firefox that still supports NPAPI plugins.
From the How-To-Geek:
Mozilla ended support for traditional NPAPI browser plugins, aside
from Flash, with Firefox 52 on March 7, 2017.
However, Mozilla offers an “Extended Support Release”, or ESR, branch
of the Firefox browser. This browser is intended for organizations to
have a stable, long-term platform that only receives security updates,
not the frequent feature updates and changes that the main version of
Firefox receives.
Firefox 52 ESR was released on March 7, 2017 and includes support
for non-Flash browser plugins. Mozilla will continue supporting
Firefox 52 ESR with security updates until sometime in the second
quarter of 2018. At that point, the next ESR version of Firefox
will drop support for NPAPI plugins.
Visit the Download Firefox Extended Support Release page to
download the ESR version of Firefox. If you’re not sure which version
to download, choose the 32-bit version of Firefox for maximum
compatibility with older plugins. Older plugins may not have 64-bit
versions available.