Which pixar films have the most popular merchandise?

The provided sources discuss box‑office performance and animated film rankings, but they contain no information about merchandise sales or popularity for Pixar titles. Because no data about product sales, licensing agreements, or consumer preferences is cited, it is not possible to identify the Pixar films with the most popular merchandise. Consequently, any claim about merchandise popularity cannot be supported by the verified evidence at hand. If further research is conducted using reliable commercial reports or official Disney‑Pixar merchandise statistics, a more definitive answer could be offered.