Ableton Multiband Compressor
The Multiband Compressor is normally thought of as a mastering tool but it can be useful on any instrument or bus. I've been using it as a way to lessen the noise on a track by adjusting the Below Threshold on the top band to begin working between notes. With the ratio being less than 1:1 anything below the threshold will be expanded and therefore becomes quieter. Its producing a more adaptable and subtle form of EQ.