Camouflage T-shirts are generally available in sizes Small to 3XL. For a list of Camouflage T-shirts see https://vtarmynavy.com/camouflage-t-shirts/. Basically if there is a camouflage t-shirt available Barre Army Navy Sells it and for a great price.
How do sizes run. We say one size small, one for the cut and two for the shrinkage after they are washed and dried. The manufacturers day they are pre shrunk but we disagree. Listed sizes are small chest size 34-36, Medium 38-40, Large 42-44, XL 46-48, 2xl 50-52, 3XL 54-56. Also note that most of this type of shirts are screened not dyed so if you wish to print over them you want to use low temperature inks. Here is one manufacturers suggestions (double click to make bigger):