Place oats, oat milk, 1 cup blueberries, 1 cup raspberries, ½ cup strawberries, almond butter, chia seeds, maple syrup, vanilla and salt in a blender. Process until oats and berries are smooth, about 1 minute. (If using frozen berries, process in the blender until finely chopped, then add the remaining ingredients.)
Divide the mixture among 4 (8-ounce) jars; cover and refrigerate for at least 8 hours. Top with the remaining berries before serving.
