What it's for: A tiny ORM that supports SQLite, MySQL, and PostgreSQL, with many extensions.
Why it's great: ORMs don't have the greatest reputation; some people would rather leave schema modeling on the database side and be done with it. But a well-constructed, unobtrusive ORM can be a godsend for developers who don't want to touch databases, and for those who don't want something as full-blown as SQL Alchemy, Peewee is a great fit. Peewee models are easy to construct, connect, and manipulate, and many common query-manipulation functions (such as pagination) are built right in. More features are available as add-ons, including extensions for other databases, testing tools, and -- a feature even ORM haters might learn to love -- a schema migration system.