Google doesn't offer a way to filter the list of apps you've installed or downloaded, but you can use your browser's find-in-page feature (Ctrl+F or Cmd+F for Mac). The list is sorted alphabetically in the Play Store site, while the Play Store app displays recently installed apps first.
Google Play doesn't even show the number of Play Store apps you've installed on your Android devices over the years. If you're curious to find the actual number, go to Google Dashboard and scroll to Play Store.
The Play Store app lets you remove apps from the list, but the Dashboard number is still accurate.