Due to the scarcity of information, legislative intent research is one of the most difficult kinds of Texas legal research. Much of the time, the official legislative history documents are the only clue to the Legislature's intent regarding a bill. Sometimes, however, the following unofficial sources will yield some additional information about intent, especially if the bill was on a major or controversial topic.
Perhaps the most reliable unofficial source of legislative intent information is the personal testimony of a bill's author, co-author, or sponsor. They are the ones who were responsible for writing the bill and shepherding it through the legislative process, including defending it against attacks from parties opposed to its passage. Talking with them about the bill can often yield a wealth of information about what they intended it to accomplish. Assuming that they can remember it, that is - some members are responsible for carrying a lot of bills and have less recollection of individual pieces of legislation.
This method of determining intent is much less viable if a long time has elapsed since the passage of the legislation. The more time passes, the more likely it is that the authors will have left public service or passed away. If the bill passed within the last several sessions, however, contacting one of its authors or sponsors is a good way to find intent information.
Fact sheets, studies, and other materials provided by witnesses to committees are the property of the committee. They are not part of the official bill file and are usually destroyed shortly after the end of a session to free up storage space. However, each committee has its own policies on retaining these materials. If you're looking for the intent of a bill from the last couple of sessions, it can sometimes be worthwhile to contact the clerk of a committee that heard the bill and ask if they have any materials from the committee hearing(s).
Another option for locating legislative intent is to look for articles in the mass media - newspapers, magazines, interest group newsletters, etc. If the bill generated some interest, even on a very local level, it's likely that an article was written about it somewhere. These articles don't always contain anything useful, but sometimes they'll have background information or provide other important local context that indicates why a bill was being considered.
Media searches can also be a way to locate personal statements, especially after a long time, since articles will often quote a person who was directly involved with the legislation. These quotes can serve as evidence of legislative intent after the fact.
In the case of an important topic or a controversial piece of legislation, it's often useful to search for scholarly articles that may have been written about that topic or law. In contrast to media sources, scholarly sources are likely to go into detail about the history and purpose of a law. The drawback to this method of determining intent is that relatively few pieces of legislation are significant enough to have a scholarly article written about them.