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.
Hard UK Drill Beat
Sample pack Alex Lustig Lost Sounds V3: Ukiyo
Loop name ALEX_LUSTIG_piano_dark_wave_emo_trap_01_136_Ebmin