In a medium bowl, combine the old-fashioned rolled oats, whole milk, and plain Greek yogurt, stirring until no streaks of yogurt remain and the mixture is smooth and well-blended.
Add the maple syrup, vanilla extract, almond extract, and a pinch of salt to the oat mixture, stirring vigorously for about 30 seconds until everything is fully incorporated.
Gently fold in the rainbow sprinkles with a spatula until they are evenly distributed throughout the mixture, being careful not to overmix.
Divide the oat mixture evenly between two 12-ounce jars or airtight containers, gently tapping each container on the counter to settle the contents and remove any air pockets.
Seal the containers tightly and refrigerate for at least 8 hours, or overnight, to allow the oats to soften and the flavors to meld together.