Re: DC fans. What to buy?
A good philosophy with small fans (I have found) is to look for the largest blade size. This means reduced blade "cutting noise" for an equal volume of air flow when compared to other smaller bladed fans. (Smaller the blade, the higher the needed RPM to produce the same airflow as a large bladed fan.) I have found the Opolar line is excellent and I use two 6" USB OPolar desk fans mounted upside down on the ceiling above my bed (fan costs under $20 rather than the gimbled sail-boat models that go for $120 or more). (I see the unit I was using is not longer made but it was similar to this model https://smile.amazon.com/BESKAR-Portable-Operation-360%C2%B0Rotate-Bedroom/dp/B087D6LR8D which was mounted on the ceiling with a single screw in the center of the base plate.)
On the wall next to the dinette I use a 9" OPolar which hangs with a simple wall hook where it can be hung and directed up or down https://smile.amazon.com/OPOLAR-Powered-Battery-Enhanced-Personal/dp/B06WGLGJ94/ref=sr_1_2?dchild=1&keywords=opolar+9%22&qid=1596417880&s=home-garden&sr=1-2
The 9" It is not as flexible in the speed department as the 8" OPolar suggested above but it is still nice and the two speeds are available. The current draw on low is around 490mA (which even meets the power capability of a laptop which is 500mA) but using the higher speed you will need a 12V to 5V or 120VAC adapter like used for a phone charger that produces at least 1A. On the high setting the 9" OPolar pulls around 720mA or 0.7A, which should be handled well by any phone charger since most of those will output up to 2A.
Now where something like an Endless Breeze is strong enough to move a small sailboat, on its maximum setting it draws about 3.4A on high, around 2.5A on medium and 1.5A on low. Keep in mind that you could turn up to seven 9" Opolars on low and that would draw as much current (and thus power) as a single Endless Breeze on high. So hopefully this will help guide and depending if you are on an "energy saving" or a "blow me away" camp.
Another one I own which I also love and contains rechargeable batteries that are good for about 6 hours on low is the "O2Cool" rechargeable model. https://smile.amazon.com/O2COOL-Treva-Portable-Battery-Operated/dp/B000VI2HT8/ref=sr_1_4?dchild=1&keywords=o2cool+rechargeable+fan&qid=1596418939&s=home-garden&sr=1-4 It's a 10" fan that can be charged and/or powered via the included 12V lighter adapter or it also includes a 120VAC adapter. The large 10" blades follow along with the philosophy to stick with large blades to keep the noise down. This fan seems a standby for the van-camping crowd as well and is just flexible enough to satisfy about anyone from tent to RV-Jamboriee special. I sometimes bungee it between my top-side roof hatch and the upper bunk curtain hooks and while it's not powerful enough to do serious air-draw like a Fantastic bathroom fan, at least it relies on the lower temperature outside air as a source when placed here rather than recirculating the interior air which at mid day can be up to 7-10 degrees warmer than outdoor ambient air, particularly if you have a lot of appliances running and also including phantom heat like from the power inverter and water heater if it is on..