x42-dpl is a look-ahead digital peak limiter based on Fons Adriaensen’s DPL-1. It is intended to be used as final step to avoid clipping when mixing or mastering, but can also be used on individual tracks as well. It comes in mono and stereo variants, the stereo version applies the same gain reduction to both channels.
A channel “inline” display is provided to give an indication when gain-reduction is being applied:
You can find more details about this plugin, and purchase a license, at the developer’s website: