You will find that Fruit of The Loom shirts are great for layering under flannels.
Sz XL (10) Pack Fruit Of The Loom Tag Free Crew White T Shirts New In Package
What stands out about short sleeves is how they balance coverage with a sporty feel.
Fruit of the Loom Men Sleeveless Muscle T-Shirt S-4XL, 3 Colors – Fast Free S&H
A nice touch is the adjustable drawstring on hoodies in S-4XL too.
Russell Athletic 631X2M Men’s Core Long Sleeve Performance Tee Top T-Shirt
A crew neck like this one makes dressing up or down super easy every day.
Bella + Canvas Unisex Retail Fit Heather CVC T Shirt Stylish T-Shirt – 3001CVC
This crew neckline is a nice touch because it doesn’t show your undershirt.