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.
The main melody of the beat is made up from two layer. A guitar melody what I've made, resampled and slowed down, and a pitched and reversed flute loop from a royaltly-free sample pack.
Sample pack Cymatics - Oracle
Loop name Cymatics - Oracle Various Melody Loop 3 - 125 BPM G# Min Flute.wav