What I notice is the crew neck, which has a slight stretch for easy movement.
Nike Air white black crest Kobe 8 24 forever mamba mentality t shirt Lakers 2XL
You will find the crew neck sits flat against the collar bone without gaping.
Nike Shirt Mens Medium Gray Grey Heather White Black Futura Sportswear New Tee
This shirt’s solid look is perfect when you want to keep things low-key.
Gildan White /black Tee Shirt Men’s Size Medium #248
This Gildan tee works great as an undershirt or on its own for a simple look.
Under Armour 1370816 Men’s UA Freedom Flag Camo T-Shirt, White/Black, 2X, Large
A nice touch on this tee is the longer hem for tucking in.