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.
Serum and a lot of shorts.
Sample pack Dropgun Samples - Arcando: Vocal Future Pop 2
Loop name ARCANDO_kit5_loop_chords_guitar_makes_me_lofi_150_A#_Min