Over on rtl-sdr.ru, Vaisili the programmer of several popular SDR# plugins has released two new plugins: an IF and an Audio Processor plugin (in Russian, use Google Translate).
The IF Processor plugin is designed to upgrade the Zoom FFT plugin that comes standard with a fresh install of SDR#. The IF processor plugin comes with a tracking notch filter and an asymmetric filter controls. These features will allow you to easily remove interfering signals that appear on top of your signal of interest.
The Audio Processor plugin allows you to improve the audio output using a controllable graphical audio bandpass filter. This feature can help you to remove any hiss or other undesirable sounds in the output audio.