FWIW
my mastering chain changes depending on the clients needs.
That said, for my own masters I’ve landed on this (for now)
Ableton eq 8. I like it’s inbuilt spectrograph and I use it for a 30hz high pass cut and any surgical cutting of problematic frequencies. that said if I’m cutting more than a couple to 3 db I’ll pinpoint the offending channel and carve it out there.
UAD Pultec clone. Just putting this in the chain creates a subtle shift in tone I like, likely odd harmonics added. I like this for boosting upper Midrange, especially in tracks that have vocals.
UAD Manley Massive Passive EQ. This is sort of the opposite of the Pultec, it’s really transparent. I’ll use this for a small boost or a resonant bump around that high pass cutoff point, and to push the highs, this is where this EQ really shines. You can push “air” really hard and it remains really smooth (depending on content)
UAD Shadow Hills Mastering Comp. Mix Glue. I rarely squash more than a couple of dB, but this too has some pleasant “color” that I like.
FabFilter ProMB. Recent acquisition and I’m still working around how much I’ll be leaning on this. Thus far I’m liking it for taming low mid mud, sort of like a dynamic EQ.
FabFilter ProL. Transparent limiting for loudness. I’m not hitting a limiter nearly as hard as I used to, I think the nature off my tracks has changed. They’re more minimal in nature and the space in the tracks needs more dynamics.
Ok there is my contribution to the now no longer soft synths thread. 
