NoteEQ is an EQ/Limiter pre-tuned to note centers.
More than a decade ago, I made a version of this in WDL (thanks Rob!) to deal with the problem of "one note bass" and dealing with overly loud or overly dead bass notes across the bass fret-board. My mastering engineer ended up using it for far more things, and I have been meaning to update it ever since. In this version, you actually have a limiter per band. In earlier versions, just EQ-ing a hole sometimes caused more problems than it fixed, but now, with the limiter, you can get a hold of the mix when its making trouble and leave it alone when it isn't! Click "E" (for Enable, were still deciding on the name) in order to enable a band (they are off by default) and "D" in an enabled band to turn on the limiter. Switch octaves with the +/- buttons under the spectrum. Note that the octaves are shown in the spectrum display so you don't have to do the math.