New ones:
Unity3D 2D Tools
Old tools:
2D Tools for Unity3D
Three C# scripts, one for making quads, one for importing textures and one for UV based animation. An example texture to show how sprite should be placed is provided too.
Muu?'s LD 2D Tools ZIP (993 downloads )
Muu?'s LD 2D Tools UnityPackage (921 downloads )