Lay out a large sheet of parchment paper on a baking sheet. In a large bowl, mix together Oreo cookies, pretzels, M&M's, peppermints, and Goldfish.
Melt the milk chocolate first by placing in a microwave-safe bowl and microwaving on high for 1 minute. *If your chocolate gets too hot and starts to harden, add 1 teaspoon of butter at a time until smoothed out*
Pour melted milk chocolate onto the parchment paper, and spread out into a large semi-thin rectangle. Let it firm up for a few minutes before moving on.
Melt the white (vanilla) chocolate the same way, and pour into the large bowl with all of the crushed snacks. Mix everything together quickly so that it is evenly coated, and then drop by the spoonful onto the milk chocolate layer. Spread gently, so as not to disturb the bottom layer.
Add sprinkles, and let cool 1 hour (or refrigerate for 10 minutes).