Are there passive attenuators that don't zero volume and only offer one input ?

Sure, Khozmo and Hattor. I just recently received a Khozmo dual mono passive attenuator with separate left/right channel volume adjustment, one input, two outputs (one for subs), all balanced XLR ins-outs, display, and remote control of all functions. I use it for remote volume adjustment in conjunction with a unity gain buffer. Discrete resistors with Takman REY metal film shunt resistors and a Vishay "nude" Z-foil series resistor.

What is the benefit of a passive attenuator that "don't zero volume"?
Is there some sonic or operational benefit?  What am I missing?
Just curious.

That coloring/softening is why I didn’t care for the sound of the Acoustic Imagery JaySho (which is basically a Bent).  That sound can be a subtle effect but it is there.  I have 3 resistor passives here now, Goldpoint, Endler, and the Khozmo that I like best.  Takman REY shunts and Vishay "nude" Z-foil series resistors in the Khozmo.  The Endler sounds a little coarse or unrefined, the Goldpoint with SMD resistors is clean but maybe a touch thin, and the Khozmo doesn’t have much of its own sound at all.  It is definitely more neutral than the Shallco volume control using AN Tantalum resistors that I took out of the signal path of my preamp - which is now a buffer.  The Khozmo was very reasonably priced considering the features and the sound quality.

@bigwave1 - The base Axiom uses a shunt to ground design that they indicate keeps the signal path away from the Alps potentiometer. I believe Joule did something similar on their preamps. The upper end Walker Mod models use Khozmo’s discrete resistor attenuators. I looked at both Axiom and Khozmo earlier in the year and went with the Khozmo. I liked the small form function of the Axiom but was ultimately able to have more/better features with the Khozmo, including L/R channel control, larger display (for each channel), and my choice of resistors. Khozmo also has an upscale brand, Hattor, with even more feature possibilities such as an active stage and more substantial chassis, but I am not convinced those would sound any better than the Khozmo line for a purely passive unit. If you want the choice of switching from passive to active using a high end op-amp or even a tubed stage then look at the Hattor line.

Not an issue to me.  I just had a passive built for me that purposely had only one input for purposes of SQ because it takes one switch out of the signal path.  If the volume doesn't go to zero then a mute switch would work fine.  I run mine in front of a unity-gain buffer and having remote control of volume, and an easy to read display, were more important to me.