There are definitely some best of lists out there, ranging from top 10 up to 50 episodes, which nowadays is 4-5 seasons' worth, especially considering the episodes are 40+ minutes.

You might search on the goog with the name of a popular website known for lists. This list covers my favorites and a few that I can't specifically recall. And 25 is a good number.

There's a few episodes where the show steps outside of itself and takes on a more humorous tone, and they're must see. Some are more scary. Some filled with solid mystery.