There are many alternatives to fseventer for Mac and since it's discontinued a lot of people are looking for a replacement. The best Mac alternative is FSMonitor. It's not free, so if you're looking for a free alternative, you could try DaemonFS or FileMon. If that doesn't suit you, our users have ranked eight alternatives to fseventer and three of them are available for Mac so hopefully you can find a suitable replacement.
FSMonitor is a macOS app that monitors all changes in the file system, including file creation, deletion, change of content, renames, and change of attributes. It provides different display modes to to examine the list of changed files.