I helped rip up the old railway platform in Waco about 30 years ago. Every brick had the name of the town it was made in molded into it. Probably a dozen or so towns as I recall. Other than that they all appeard the same. Larger than modern bricks. I took a truckload or two home and laid a patio with them. Looked really nice.
I once got a bunch of ancient bricks that were original when Fort Worth first bricked some roads. Then one day they were missing. Found out that grandsons had hauled them to the stock tank and were using them as fish attractors. They are still there.
I've got a small old brick collection. D'Hanis is of course the most common down here. I think I have a Mexia. 'Have an old Acme too. I worked at the Denton Acme plant when I was in college. 'Loaded them in the kiln and had to go after the stuck carts with a winch, wearing a fire suit, after the kiln was shut down. That's an eery feeling. I was also a greaser some nights. True story.
There were dozens of brick companies across Texas. I watch for them same as I do hunting arrowheads, fossils, and such. Walking creeks and rivers is always fun. You never know what you might find. My flower beds are lined with old bricks. I have found some real interesting ones and ones local to me. The Carrollton bricks I have are over 100 years old. One could find them in a creek in Carrollton next to where the brick factory had been built in 1904, but it has long since been rechanneled and rocked, so no longer.