There are apparently different narrations (though I've only found subtitles, not necessarily audio files) for the age ending cutscenes, depending on what legacy path (if any) you finish, there are even two versions for culture each:
There are also subtitles for victories in ages earlier than modern and legacy path cinematics for modern age civs? Including 7 alternative defeat narrations for Qing????? It's surprising that there are those but masteries don't have unique quotes.
There are also unique cinematics for all 21 leaders, I have no idea how or where they appear in game. They're in fact 21:9, not 16:9, this applies to all civ background art (which is displayed as a cropped 16:9 version for example on loading screens for some reason). It seems like its what the leader banners are based on. I have never seen this art in full before.
I bet that Catherine's one was done by the same person that painted the French background art. Look at the eyes and the skin texture!