Before the dominant, the chromatic approach chords. The Neapolitan sixth is the major triad on ♭2, sitting in first inversion — a dark step toward V. The three augmented-sixth chords (Italian, French, German) all hide the same interval: an augmented sixth between ♭6 and ♯4 that splays outward by half step onto the octave 5̂, dragging the ear to the dominant. Pick a minor key, choose a chord, and hear it pull to V — every note spelled correctly.
Pick a chord above.