In our country we have long TV series (maybe seventy episodes in one series) without unique titles. They are just simply marked as episode 01, episode 02, etc. It is hard to find the specific one in so much meaningless number. But in English TV series we can easily find, for example, the sad episode when our character dies, because of its title Swan Song.
Not only that, these titles are not simply describing the plot. They often have a clue, snark or pun. I googled for "TV episode title"; the articles about how to write this kind of title say TV episode titles have a tradition of being "clever". So, is there any term to describe these tricks? I know not everything has its own vocabulary, so any short and unambiguous way to call that style is fine. It would be better if Wikipedia has related entries.