The National Association of State Chief Information Officers recently put together a State Mobile Apps Catalog with information about government apps provided by all 50 states. Currently, it contains over 160 apps in a number of categories such as business and corporate filings, legislatures, professional license search, and tax and payment services. You can choose to view the government apps in each state or view apps by category.
Right now, the available Texas apps are the Texas Driver Handbook, Texas.gov, and TX Senate Business & Commerce. Once you find an app of interest, the catalog provides a short description and a link to the app store where the app can be downloaded.