Sweet, nice, flowy songs..?

i agree with all of @TommyLambert's suggestions but u asked for unkniwn so i'd say Marching Bands Of Manhatten by Death Cab For Cuties or I'll Follow You Into The Dark by Death Cab For Cutie, even though they're sorta sad and romantic at the same time. i'd also try Innocence by Avril Lavigne...soooo sweet!!