Some other ones are obvious, such as boss remixes of characters' general themes. 'Undertale''Once Upon a Time''Home''Hopes and Dreams''SAVE the World''Reunited''Hotel''Can You Really Call this a Hotel? I Didn't Receive a Mint on my Pillow or Anything''His Theme''Memory''Menu''Start Menu''The Choice''Fallen Down (Reprise)''Bring it in, Guys!''Last Goodbye''Good Night' For instance, the three melodies used in the game's theme song, 'Undertale', appear in about half the soundtrack, including: The melodies are used intentionally and cleverly, and are very meaningful to the situation in the game.
Toby Fox composed the entire soundtrack himself, and often reused melodies that appear throughout the game to induce nostalgia in the player (reusing melodies also made it a lot easier for him!). Undertale has one of the most extensive soundtracks of any video game I have played.
