Gamedev Framework (gf) is a game framework, it provides some useful features for developping 2D games. Here is a short list of some of the main features of gf:

Core
- Vocabulary
- Container
- Maths
- Geometry
- Colors
- Models
- Messages
- Procedural Generation
- Spatial
- Animation
- Roguelike Toolkit
- System
- Filesystem
- Streams
- Serialization
- Utilities
- String Utilities
- TMX (Tiled) Support
Graphics
- Input events
- Window and monitor
- Devices
- GPU Resources
- Renderers
- Views
- Drawables
- Sprite display
- Text display
- Shapes
- Curves
- Tiles and Tilelayers
- Particles
- Virtual console
- Widgets
- Resources
- Entities
- Scenes
- Post-processing
- Segues
Network
- Network sockets

If you are looking for a full game engine, you should take a look at the list of game engines on Wikipedia.

See also: The Engine FAQ on /r/gamedev wiki