Any federal reporter publishing decisions of courts adjudicating federal tax disputes can contain judicial tax case law. Below are links to a selection of reporters focusing on cases involving federal tax issues. For the most part, the titles of the reporters inform on the types of cases covered by the individual publications.
Below are pertinent abbreviations.
A range of courts–including the U.S. Tax Court, U.S. Ct. of Fed. Claims, U.S. district cts., and U.S. appeal cts.–adjudicate disputes involving federal taxation. So, reporters publishing the decisions of these courts will offer judicial opinions relating to federal tax issues.
The U.S. Tax Court issues three types of decisions:
"The U.S. Board of Tax Appeals is the predecessor of the United States Tax Court. Prior to 1942, the Board of the Tax Appeals was the prepayment forum for taxpayers who wanted judicial review of the Internal Revenue Service’s determination of deficiencies in income, excess profits, and estate and gift taxes." (U.S. Board of Tax Appeals, IRM § 18.104.22.168.9.1)
Fore more information, see McDermott's very helpful Types of Tax Court Opinions and Their Precedential Effect