I think you will find that there aren't a whole 'slew' of HF vertical antennas. Most manufacturers do make them, at least one, sort of, but nothing like is available for the higher HF bands. The primary reason is that the lower you go the bigger them things are going to get! At least if you want 'reasonable' performance from them. One other thing about HF verticals is that like it or not, the lower you go in frequency, the more noise you are going to hear.
Also keep in mind that I am not a huge fan of HF vertical antennas. I have used them, they do come in handy, and they do have their good points (as well as some bad ones). Not having a vertical hasn't stopped me from enjoying HF stuff, they do not have any overwhelming benefits over 'non-vertical' antennas.
Having said all that, there really is one vertical HF antenna I wish I could afford. I've heard several that have been really nice in their abilities. Aside from the $$$ part, they also require some preparation for good performance. (As in a very good ground system, radials in dirt, not ground rods.) "Mississippi's Finest Junk" owns the design now, used to be by 'Hygain'. Getting a 'clue' of which one I'm talking about? You're probably right, the 'HT-18' or '18-HT' not sure what they call it now. Does all but 160 meters very well, good coverage. Does 160 meters too, but only a 'chunk' of it, not all of it, which is 'normal'. It ain't small. Then again, what you can expect from it isn't 'small' either.
All the above is for commercially available 'resonant' antennas. But if you'll think about it a bit, what says it has to be 'resonant' at all? There are over 4000 of them things around the country. Most if not all of them are 'custom' built antennas. They work just fine. They do require 'matching' or a tuner. Most of them are much larger than that 'HT-18'.
What are they? Ask 'QRN', bet he knows...
- 'Doc