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.
There is a reversed and processed key loop and some other made from scratch instruments coming from MTProLE VST.
Instrument Main Sample
Sample pack Slate Digital - Pasadena Pop Sample Pack
Loop name SD_PASADENA_songstarter_godetia_140_Am