MLS beat me to the meatloaf idea. I do the same thing by using oatmeal in place of breadcrumbs. I think it improves both the flavor and texture. You can substitute the oats without making any other modifications to the recipe.
You can whiz up the oats in a food processor to get an oat flour, which could be used just about anywhere you’d use regular flour. When one of my acquaintances went on a gluten-free diet, they did this. I tried a muffin they baked that way… while it was a little different in taste/texture, I didn’t know what the change was until they told me. (They also did the applesauce substitution for cooking oil, so there were a lot of tweaks on these muffins). Overall, very tasty.
And then there are options I haven’t tried. Apparently, you can think of oats pretty much in the same way you’d use other grains that come out creamy when cooked such as grits, polenta or risotto.