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.
Bass VST Sylenth1, Mix and master plugin UAD.
Sample pack Toolroom - Leftfield Bass
Loop name TA_LB_SYNTH_LOOP_SYSTEM_125_F#