I don't think the brands even matter. Just look for old stuff - typically the buttons end higher up on the shirt, because they were made to be tucked in. I know the old Big Mac ones sell well, but basically as long as they are actually old and have a cool pattern, they are desirable. I think the two pockets also help out.
Couple things to look for on these also is the loop button collar, flap pockets are a plus, making sure it isnt overshrunk since they are cotton, and if made in USA is good...but also if being sold to Japan, they like made in Japan as well
Don't forget CPO shirts, i.e. heavy flannel, with the same type of button but smaller you find on Pea Coats (has an anchor). These are kinda hit and miss but if you can get cheap should be able to make some profit.
(Ugh..sorry I continuing the Ebay/Flip push.)