Another gem from Astute Graphics, offers a free version that is surprisingly powerful. It brings much-needed color adjustment controls to Illustrator that behave like those in Photoshop. You can control Hue/Saturation, Levels, and Curves directly on vectors.
CFS offers a set of free utilities including a (to round or invert corners instantly) and a Texturino Lite (for applying grain textures without masks). illustrator plugins free