Takes years to find. I have lost a nice audio CD more than 16 years ago. I still have not found all the various songs that were in it. Songs like to mega therion and the lord of boards. Some I could find quickly because I could remember the lyrics but those I know only the tune. Very hard. Still looking for some.
I had this happen a few days ago when I randomly thought of a song lyric and could not for the life of me remember the song. I searched the fraction of the sentence I remembered and found it.