As as junior apprentice audio mixing engineer, I've been experimenting lately with adding effects, such as a touch of ProChannel Tube and/or reverb, to the Master Bus Effects Bin, and am generally pleased with the results.
 
Do you seasoned pros have thoughts about this?  What's in your Master Bus Effects Bin?
 
 

The Glue by Cytomic followed by ARC (which I bypass for a bounce).

(edited for clarity)

A Boost 11 to stop anything nasty getting to my monitors.
Grum.

Vintage Channel (start with the Master Mix preset) L64 Multiband (start with the medium setting) Boost 11 (or Waves UltraMaximizer if u have it) I occasionally use a reverb on the master bus, but usually, I use reverb in an aux bus so I can set different levels of reverb for different elements of the mix. But the trinity above is my default master bus setup. it works on almost everything (with a little tweaking).

As each song will need different things, the master bus will have different plugins on it. I generally never use reverb on the master bus, as that's an effect that i use on a bus and ill have sends on the tracks going to it.  

But usually its EQ, compressor, EQ(mid/side), limiter and an analyzer/meter and 3 of the 5 are usually hardware effects and sometimes its just 2 of the 5. It all depends on the song at hand.

Cj

Always: Sonitus EQ, with only band 1 on, doing a gentle LF rolloff from about 38 htz down.
On RARE occasions I may also do some VERY teeny Eqing of the highs or mids - but only very gentle (wide bell curves, no more than 0.5 db +/-).
While I am writing and tracking, that it all that is there.  When the song is completely done with the mix, and ready to be shared, I will add Izotope Ozone 5, usuallly only doing a teeny bit of limiting (not slamming, just "helping").

If its mastering its Ozone, If its mixing it can be a number of things, some of them could include LP-64, LP-mlutiband, VC-64 Vintage Channel, Channel tools, and third party plugs. I don't always use the same plugins for mixing. One of these days I am going to see what R-mix can do. Not sure about that one.

If I use the Pro channel on the master bus then I may use pc4k-s type bus compressor, console emulator bus, PC2a leveling amplifier, and the concrete limiter. I have even used the PC4k exp / Gate a few times.

Absolutely nothing. I do that stuff in a new project.

Voxengo plugins, GlissEq-Polyquasher-Elephant from the very start of composition then adjusted at the mastering stage.

ProChannel EQ, Waves L-1, Waves CLA compressor of choice