There are several synonyms for the phrase "riddle canon." One of the most common is "mystery collection," which refers to a group of enigmatic stories, riddles, or puzzles related to a specific theme. Another alternative is the term "conundrum anthology," which describes a compilation of complex or tricky problems that require careful consideration to solve. Other options include "brainteaser compendium," "puzzle catalog," or even simply "riddle collection." Regardless of the terminology used, these phrases all refer to a curated selection of challenging mental exercises designed to test one's wits and problem-solving abilities.