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.
Process note
Plugins:
Main Bass (Serum) - Mid (Sylenth1) - Sub (Serum) - Reece (Serum)
Pad (Serum) - Keys (Kontakt) - Strings (Kontakt) - Chords (Serum)
Plucks (Spire)
Melodic loops
Instrument Piano Melody (Break)
Sample pack DS0017 Vocal Future Pop (Sample Pack)
Loop name VFP_kit3_break_melody_piano_wet_166_g_minor