Singer Lena Park has built up a vault of breathtaking ballads over her long career, most featuring her airy voice lifting off over smooth, glassy keyboards and string swells. She's mixed up the formula too, using acoustic guitar and jaunty piano as the backdrop to “Damage” and jazzy ukulele and slide guitar for the moody, whimsical “Winter.” This list highlights some of her sonic detours, along with soaring, fan-friendly ballads.