One parameter than many engineers overlook is the envelope of the sound they're processing. Sure, you can change it with a compressor, but sometimes you need more control than a typical analog-style processor can give you, and that's where an envelope shaper comes in.
Sonnox has taken this concept to another level with its new Oxford Evolution frequency dependent envelope shaper plugin, which has separate transient and sustain sections that allow you to radically re-shape the envelope of the sounds you're working on.
Evolution is great for adding extra snap for drums or percussion, boosting sustain to keyboards and guitars, for smoothly controlling leakage in a track. It comes with a attack, release and hold controls for both the transients and sustain, as well as a master control for each, and the ability to alter the main frequency band that it's operating in. A DIFF button (similar to a Listen control on a gate) allows you to hear only the effect, and a Warmth control adds harmonic saturation.
The Sonnox Oxford Evolution plugin is available for AAX, Audio Units and VST formats and costs $270 USD. There's a 15 day free trial period available. Here's a video that lets you hear how it works on various program sources.