I skimmed through 20m voice on Monday afternoon. Only a couple or so active QSOs. Admittedly I was using the 148' loop-on-ground, which is not exactly a great 20m antenna, but still. o.0 IIRC, 40m voice was not much better.
Further up the HF bands, I used to occasionally talk on 11m SSB back in the day, but I have not bothered in a *long* time. Ideally, just a few watts with a simple dipole or vertical can work much of North America.... if ya' can find actually workable 11m propagation. I am not saying 11m is deserted completely, but even 27.025 has been mostly static here more often than not for quite awhile now.
10m SSB largely is vacant here, too. Further up, has anyone heard 10m FM simplex in recent months... err, years? Last time I even heard one of the now seemingly elusive 10m FM repeaters probably was a year or two ago.