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.
Classic House Track.
Instrument Filter Loop 2
Sample pack Loopmasters - Freemasons 100% Remix Tools
Loop name FRM_128_Dmin_3_AIR_11