Starting out with the most obvious of choices: straight-up denim. Usually a lighter weight than your jeans (it would qualify as a jacket, otherwise) at about 8 to 10oz. Many denim shirts are created in a western style pattern, with pearl snap buttons and a tapered yoke on the back. The chest pockets have different styles: the Barstow (a single point on the flap) and the Sawtooth (two points on the flap) are the most popular styles. We carry (western) style denim shirts from several brands like Full Count, The Flat Head and Samurai Jeans.
Chambray
A fabric that has already been around for centuries. This fabric is usually easier to wear than a denim shirt, due to the light plain-weave invented by weavers from Cambric, a city in the north of France. They originally named the fabric after their city, but the name 'chambray' replaced 'cambric' in the early 19th century in the United States. You'll often see chambray shirts in grey and light blue tones. This indigo-dyed version by Trophy Clothing is a fine example. Chambray used to be popular in the working class for a long time before the US Navy also included it in their uniform options, offering trousers and shirts out of chambray.
In the 1830s, a company called Stifel introduced their version of chambray which had a trademark identifier: vertical rows of tightly placed dots, which look like stripes (or even a formal pinstripe) from a distance. The dots were made by adding small drops of starch in continued lines down the fabric which didn't allow the indigo to settle, creating the pattern. Stifel produced work clothes like overalls for railroad workers, but has been out of business since 1957. Luckily, several Japanese companies still offer wabash shirts like UES and The Flat Head.
Hickory
As wabash, hickory finds its roots in the railroad industry as well. A thick, durable type of fabric that was capable of withstanding hard days of work. The fabric can easily be recognized with the blue and white stripes, and was made by all-American companies like Lee and Pointer. Nowadays we can enjoy propper hickory by UES.