Note that this achievement only seems to count the 10 songs that come with the game and not the DLC. I did nine of those songs and then one dlc song on Beginner and the Achievement Progress went to 100% but did not unlock. Once I did the last Base game song on Beginner, the achievement unlocked for me.
The following songs are part of the base game if you lose track:
#thatPOWER
Counting Stars
Diamonds
Happy
I Wish
Royals
Show Me
Talk Dirty
Titanium
Wake Me Up