The rules of the State Bar of Texas set out standards by which all fees, not just contingent fees are judges. These are enforced by the courts and the State Bar's grievance process. No set amount or schedule is used. In certain cases there are limits on the percent, but in most cases it is based on the State Bar rules.
This is not legal advice. You should always discuss the specifics of your issue in person with an attorney. Be aware that there are time limits on all claims that depend on the kind of claim, so do not delay in seeking an attorney.
Texas does not have any such schedule. Contingent fees, with the exception of those charged in certain special kinds of cases, such as workers' compensation cases, are not capped in Texas. Texas Disciplinary Rule of Professional Conduct 1.04 prohibits fees that are either illegal or unconscionable. Paragraph (b) of the rule sets forth the criteria by which the size of a fee is to be judged under the rule. Rule 1.04(d) deals with contingent fees specifically, but it does not specify any maximum percentage that lawyer may charge.