There's no single list that all of us refer two. There are two or three major lists which order many pieces by their level of difficulty, but I'd say the majority of students don't pay much attention to any lists at all. Knowledge of piano repertiory simply comes from having a lot of experience with it. Going to concerts, buying CDs, playing the pieces yourself - it all adds up. I don't possess a great deal of knowledge when it comes to repertoire, but there are some pieces which many people know simply because they are played very frequently. Here's a small sampling off the top of my head...
Beethoven - All of his sonatas, but most notable the Moonlight, Apposianata, Hammerklavier, and Pathetique.
Chopin - Etudes, Nocturnes, and Scherzos. Most notable the Scherzo in B minor, Revolutionary Etude, Nocturne Op. 9 No. 2... hell, almost all of these are very well known, it's silly to point out single ones.
Rachmaninoff - Prelude Op 3 No 2, Prelude Op 23 No 5, Concertos 2 and 3
Liszt - La Campanella, Hungarian Rhapsodies, Transcriptions
Bach - Well-Tempered Clavier, books 1 and 2 (preludes and fugues), English Suite, French Suite, Partitas
Well, it's really silly to list all of this. There's much too much music which could be considered particularly popular, but you get the idea. Exposure to classical music will eventually impart some knowledge upon you.
