for me i'd say any song that has something to do with being extremely in love with someone ("nothing without you" or "crazy about you" type of lyrics)
songs that have to do with being extremely depressed/loney/not being cared for.
or songs that are about just enjoying life and being happy. sadly i haven't gotten to that part of life yet, and im a nightmare to deal with/be around, and not really enjoying life. so while i do enjoy listening to these types of songs, it is likely going to be several years until i can live with the past, and hopefully be anxiety free like before (i can easily say that i enjoy being extremely stressed far more than anxiety)