An affordable classic, Hanes makes the best by-the-pack undershirts out there. The V-neck is low enough not to show, but not so low to embarrass you when worn by itself. (3-Pack)
Designed for performance and engineered to stay tucked-in, but built for comfort from 18-hour jersey with rotated shoulder seams and a wide, deep V-neck collar.
Handmade from the softest cotton, this classic tee from Sunspel has a low, rounded-V neckline, which makes it easy to be worn (but not seen) beneath an open shirt collar.