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.
Made a reverse piano and layered with a nice lead. Then, i sequenced all the drums and 808.
Sample pack Misfit Digital - Digital Contraband Trap Vol.1
Loop name Kit 1 D#min 130_lead