Sometimes engineers have all those discussions about "the best" plugins, well in my opinion there's no such a thing as "the best" because it comes down to personal preference and taste. So.. here are my 3 favorite filters.
#3 Avid EQ3 7 band
Yes, stock Pro Tools plugin. A lot of people don't even consider using stock plugins because they "suck" at least that's what they say. The filters on this thing work great. Workhorse when it comes to quick cuts and super CPU efficient. I use it on every mix, obviously different way each time.
#2 McDSP FilterBank F202
One of the best filters I have ever tried. Nice curves, cuts, simply amazing plugin. McDsp really created a perfect tool, whether it's for mixing or mastering. It adds extra color (at least that's what i think, not a lot just a touch). The boosts of EQ (peaks) are also magical, as long as it's not too much.
#1 UAD SSL E Series Channel Strip
This plugin itself is simply one of the best (when it comes to my taste) The filters... honey and milk that's how i can describe them, there's actually 2 different curves for the EQ filter section. Black and brown modeled of 2 different SSL EQ Sections. Great for any type of source, really easy to cut out the unwanted lows and unnecessary highs. My favorite all around filters, especially for vocals.
Universal Audio Website
Worth to mention
UAD Dangerous BAX EQ
M/S Mode is what this plugin is all about, filters but not only that.
Lovely M/S Filter.