OFFICIAL PAGE: Ghost-X (website no longer active)
Ghost-X, from BlueLab | Audio Plugins, is a inexpensive Spectrogram Visualizer and Editor which can be used as a standalone application or as a AU / VST / VST3 / AAX plugin on both macOS and Windows. In addition to the ability to copy, paste, and cut regions, you can also select regions and increase or decrease the levels within those regions. A powerful inpaint tool is included for replacing a region by the expected background. A set of eight colormaps, as well as brightness and contrast controls, are included so you can tailor the spectrogram to your preference.
Screenshot courtesy of Christopher Kissel