Into the Unknown - Music and lyrics composed by Kristen Anderson-Lopez and Robert Lopez for Frozen II (2019). Performed by Idina Menzel. Menzel first sang the song in her dressing room backstage at an off-Broadway play, with Anderson-Lopez and Lopez bringing in a keyboard to provide the music.
In Summer - Music and lyrics composed by Kristen Anderson-Lopez and Robert Lopez for Frozen (2013). Performed by Josh Gad. According to Josh, since Robert Lopez had already co-written The Book of Mormon (in which Gad played Elder Cunningham), Lopez already knew what type of voice he had, and so that influenced the type of song that was written for him. Gad also appreciated being able to perform a song "without 20 f-bombs in it", so it was acceptable for a younger demographic. The songwriters asked him to do "the operatic ending", a request that amused Gad.