Covid-19: For updates and resources, head to UT's Protect Texas Together site.
US Copyright Office's Fair Use Index: searchable database of court opinions, including by category and type of use.
Besides case law databases on Lexis and Westlaw, there are two specialized reporters in IP law.
BNA's United States Patent Law Quarterly (USPQ):
CCH Copyright Law Reporter: Westlaw (login required)
Resources on Uniform Laws
ALI's Restatement of the Law, Unfair Competition: Online and KF 3195 R472
Because trademark law may vary state by state, it can be useful to compare and contrast the laws between them. If you are lucky, someone may already have done a fifty state survey on your topic. To see if a survey already exists, check out these resources: