If you had to choose a single light shaping tool, you might do well to pick the Hudson Spider 7' White Translucent Umbrella for Mozzie LED Fixture. The umbrella is broad light source that wraps light around your subject yielding clean highlights and rich open shadows. But due to the special shape of the umbrella there's a unique mix of soft enveloping light with the kind of crisp detail you only get from reflectors.
This white diffusion is the softest version of the umbrella. Used in standard bounce mode, some of the light escapes through the material, slightly raising the ambient light level and lowering contrast, while most of it is directed towards your subject. If you want a harder light, turn the umbrella around and aim the convex side at your subject and punch your light source through it. You can also use this umbrella as a scrim over your subject to diffuse harsh light sources like the sun in situations like fashion catalog work outdoors or at the beach.