Pure reference catalog of the cross-language object-construction patterns for test data - Test Data Builder (Pryce/Freeman), Factory (with traits and associations), Object Mother, Fixture composition (per-test / per-describe / shared), Snapshot (defers to `golden-file-conventions` for the operational details), and Production-Data Anonymisation. Distinct from the per-language tool skills (`faker-data` and the `synthetic-data-toolkit` umbrella covering FactoryBot / mimesis / Bogus) which document tool-specific configuration; this catalog is the architecture-tier reference for choosing **which pattern** before reaching for the tool. Use when choosing a test-data construction pattern for a new suite, or auditing an existing suite whose fixtures have drifted into shared mutable state.