I've owned the B7K and have had a Tone Hammer for years. The B7k is a really good preamp, but it doesn't quite qualify as truly parametric, if that's a primary feature you're looking for. Plus, it very much has the Darkglass Sound. And it's more of a preamp than just an EQ if it matters. Similarly, the Tone Hammer is also more of a preamp with a baked in Aguilar sound, but it does have an actual parametric mid.
I parted ways with the B7K (and the Vintage Ultra, and the Alpha Omega Ultra) because the EQ sections were clean, but they're almost TOO clean... they lack a warmth that I missed with the Tone Hammer. My theory is that it's because the Darkglass pedals have low control points of 80Hz or 100Hz depending on the model, and the Tone Hammer's low control is centered at 40Hz. A little more warmth and oomph in the low end. But, the Darkglass stuff is very much geared for a specific genre, and Doug is
very good at designing pedals that
really work for what they're designed for. They just weren't quite what I wanted.
I've never tried the Empress, but it does look quite nice.
+1 to the Qstrip. I've had one on my board for about a year and a half (ish), and love it. Two parametric mid channels that overlap a bit (and also with the low and high controls), so it's pretty flexible. Lately I've been experimenting with settings lifted from Jayme Lewis' demo video of the Trickfish Minnow and have been quite pleased.
The Tone Hammer is simply too good to get rid of and occasionally swaps in for the Qstrip. It's pretty killer with just a smidge of the AGS dialed in and high control toned down for a thicker more vintagey sound. Currently though, it's the preamp I'll use for an alternate board build with pedals from the toy closet when I get around to it.
I'll put another +1 for the Source Audio EQ2 that @LSMFT6 mentioned. No personal experience, but Source Audio is top tier gear IMO.
If you
really want to go down the preamp rabbit hole, check out the
Great Preamp/DI thread. LOTS of great preamp/EQ discussion over there.
5sg.