The base is original from the producer (chords and melodies), but is complemented with elements that complement the song that come from samplepacks, usually, vocal chops, guitars, wobbles sections, glitch effects. It is the standard in which most of producers work, in a project you will find MIDI files made by the producer, but also melodic loops.
Track produced by me, drop made with a sample pack by Barely Alive, modifying Pitch and building a totally different drop line.
in the break part the melody was created by me, resulting in this high level track.
Sample pack Barely Alive - Essential Samples
Loop name BRLY_ALVE_bass_coocoo_Eb