A raw oats porridge can be made with hulless oats. Although they can be a bit more difficult to digest than cooked oats, these oats may be the only ones that are "truly" raw.
Hulless oats are the forgotten type of oats. Its loose hull falls away during harvesting and it does not need to be milled like conventional oats.
Therefore, hulless oats have a much better chance of being raw because they do not have to be damaged by heat created by the de-hulling practice.
And the health benefits of oats are numerous and include being a good source of important minerals as well as vitamins.
Raw oats should always be soaked before you eat them to get rid of the anti-nutrients found in most grains. And it may be more effective to soak them in acidic water (lemon juice or raw apple cider vinegar).
And to the best of my knowledge, humans are not capable of digesting grains like raw oats. At the very least, you should put the soaked oats in some hot water and let them sit overnight.
And it is my understanding that oats are a gluten free grain, unless they are grown and processed with grains that contain gluten.
Naked or hulless oats are probably the least well known from the oat family. And the origin of this particular type of oat appears to come from certain regions of Asia.
The nutritional profile of naked oats is impressive - it is higher in protein and fat than conventional oats.
Along with being more nutritious, hulless oats are known for having a mild sweet taste. Also, this type of oat is tender and sprouts quickly.
Hulless oats do not do very well with mainstream agricultural practices and is best left to smaller farmers to grow.
You could grow your own and probably find these seeds at a good seed company. It should be found under the name Avena Nuda or Hulless Oats.
I have never seen this type of oat in a store, but I've seen them online.