I have a "Honeywell Turbo Force Oscillating Table Fan, HT-906," in the 9" class. I've hung it upside-down, allowing it to be aimed downwards some, and it's been running continuous on low for about 8 months now with no noticeable noise. For your tent, larger than mine, you could just put one in different corners. I also have a larger Honeywell Turbo-style fan running at the top on low providing whole tent vs. localized air movement. This works better, is simply quite, compared to the more expensive oscillating Monkey fan I had that died after a few months. And they are rather cheap and likely even at local stores.
Otherwise, I think Vornado fans are overall the best fans, but cost more. They have a few oscillating models. If you need it to be really quiet, consider an oscillating Dyson fan.
Before buying an oscillating fan for tent use, check its manual online. Many have limits on tilt while oscillating; some don't tilt downward at all; can't be mounted upside-down (allowing higher mounting), etc.