The Verbum Entropic Hall plug-in uses a chaotic reflections algorithm to create a reverb with a character that's reminiscent of early reverb machines...
Conventional compressors or expanders are not always suitable for tackling issues that affect only one part of the frequency spectrum, which is where multiband solutions like Pompeii come in very useful.
Submarine's role in life is to add natural-sounding sub-bass content by generating frequencies that are one octave and two octaves lower than the input signal.