Over the years, I've accumulated examples of illustrated covers produced and sold by several printing houses in Texas (and elsewhere) directed towards county officials for use in their business. I've even observed one that had a Attorney's corner card, so apparently they were available to anyone who wished to make a purchase.
I've encountered examples for perhaps 25 of the 254 counties so far, but admit I've not made an exhaustive study or census.
I've encountered several basic designs, and here are two.
The first includes the official's name and title in an oval. This pone seems to appear most often in the post 1900 period. The latest use I have seen was 1932.

The second variety places the name and title in a rectangle on a slant. These appeared in the early 1890s, and are not seen often after 1900.

Both designs have the five pointed star and wreath, both elements of the State Seal of Texas, in the center of the design.
I've identified four different firms who produced these. Three were in Texas and were related over time. The fourth was in St. Louis, MO.
I recently showed these to a friend who collects Iowa postal history, and he observed that he had not seen anything like this used in Iowa. This got me wondering if other states has similar envelope designs used for county offices.
Texas uses a different design style for State Government offices, and these I do see form time to time for other states.
I invite anyone with similar covers from other states (or even Texas) to add them to the thread.
Mike