1. Car Evaluation: Derived from simple hierarchical decision model, this database may be useful for testing constructive induction and structure discovery methods.
2. Lenses: Database for fitting contact lenses
3. MONK's Problems: A set of three artificial domains over the same attribute space; Used to test a wide range of induction algorithms
4. Trains: 2 data formats (structured, one-instance-per-line)
5. Reuters-21578 Text Categorization Collection: This is a collection of documents that appeared on Reuters newswire in 1987. The documents were assembled and indexed with categories.