These are surprisingly hard to find, especially if you want relaxed fit and not skin tight. My favorites are Champion c9 relaxed fit from Target, but they don't have any this year. Walmart carries a relaxed fit from Danskin that is OK, but not as soft as the Champion. Sierra Trading has a Carhartt Force T-shirt that is also relaxed fit, but they are out of XLs.

Ex Officio, Under Armour, Lululemon that I have tried all fit like a second skin - NOT the look I am going for!