SchemaCrawler is a free database schema discovery and comprehension tool. SchemaCrawler has a good mix of useful features for data governance. You can search for database schema objects using regular expressions, and output the schema and data in a readable text format. The output serves for database documentation, and is designed to be diff-ed against other database schemas. SchemaCrawler also generates schema diagrams. You can execute scripts in any standard scripting language against your database