I'm getting ready to have a pole barn built. Does anyone have advice regarding ventilation? The building will be used for a barn and won't be heated or cooled. I'm considering ridge vents, gable vents, or do nothing. Any thoughts.

What's the intended use?
What's the footprint of the barn?
What's the purpose of the ventilation system?
Where are you located?
What direction is the prevailing wind?

Your options for a pole barn, as you have surmised, are pretty limited, but there are a few things you can do. And before everybody piles on and recommends a BigAss Fan or Portacool, knowing what you want from the system can help us help you.

Thanks. The building will be used for equipment storage and will have a couple of horse stalls to use occasionally during cold weather. I was hoping to find folks that built barns with or without vents and if they would have done it differently a second time. The purpose of the ventilation is to allow heat and moisture that would be trapped within the building to escape.

https://www.hansenpolebuildings.com/?s=ventilation

I forgot to ask - open sides or enclosed? Where is the barn located?

Barn is in eastern OK. Closed sides.

With closed sides, orientation won't matter as much. Ridge vent with soffit vents for winter time, and windows/doors for warm weather. Depending on how many horses or other animals, you may need to consider additional fans to pull out moisture. Talk to your livestock housing extension specialist at OSU for more specific regional recommendations. There's some good folks at UK for this sort of thing too. In lieu of that, look at some of the Midwest Plan Service barn design info.

The link provided above is a good primer, read and understand it. EVERY enclosed building needs a way to get rid of moisture in the winter. Even my FIL's 30x40 insulated shop with an epoxy floor needed some help.

Insulation will help immensely, even if its just the roof.