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.
Breakdown bass is made in Serum and layered with chords, which is made with 2 modified FLEX piano presets. A royalty-free synth loop is used to give the breakdown more energy and is edited (lower tempo and pitched) and is also heavily processed with different effects. The drop bass is designed with Serum and the lead sound is made with 3 different Serum layers, a bright synth, a wide saw lead and a pluck sound. Some FX, ambience and vocal FX are used to complete the track!
Sample pack Hybrid Vocal Trap
Loop name HVT_kit1_brake_melody_pluck_01_150_c#_minor