Or grey noise, whatever works.

There's a whole spectrum of colors of noise. All similar, but different.

I use this one at very low volume - lots of indistinct background sounds like people talking that you can't make out the words to, rain, gentle overall music, etc. Been using it for nearly two decades (found it elsewhere initially, so ignore the date uploaded), and it rarely fails.

ETA: Warning that it does have a very slow buildup in volume for the first 30 seconds or so - just skip into the track a bit to sample it.