Done.
Only two “below the line” 
I’d be happy to argue for it to be a replacement for “Cross Fade Out” as a useful alternative to the linear Fade Out. I suspect that “Pro Fade Out” will be more useful to more people, more frequently than the “Cross Fade Out” effect. Custom keyboard shortcuts work great with this.
I don’t think that there is a directly equivalent “Fade In”, because there tends to be a lot of variety in the most appropriate type of fade in for particular jobs. I’d rather replace the Cross-Fade In with a more versatile effect.
The “Fade By dB” effect is pretty popular: Simple plug-in for creating partial fades
The main “selling point” of this effect is that it can do a partial (not to silence) fade.
The version of “Fade by dB” that I use has 4 fade shapes - “Sine” (“S” shape), “Convex” (like “Cross-fade in/Out”), “Linear” and “Log” (like “Envelopes”).