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.
In this project I used Serum, Arturia CMI80, Diva, Hive.
Sample pack Unison Artist Series - Marc Depulse _Melodic Indie Dancers_ Vol. 1
Loop name UNISON_MDP_MELODIC_Singing Love (122BPM - Gm)