Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large mixing bowl, cream together the softened butter, brown sugar, and white sugar until light and fluffy using a hand or stand mixer fitted with the paddle attachment.
Add in the eggs and vanilla extract, mixing until well combined.
In a separate bowl, whisk together the all-purpose flour, baking soda, and kosher salt. Gradually add the dry ingredients to the wet ingredients, mixing on low speed until a dough forms.
Once the dough is formed, gently fold in the mix-ins: semisweet chocolate chips, toffee bits, caramel bits, crushed potato chips, and crushed pretzel pieces.
Use a cookie scoop to portion out dough balls onto the lined baking sheet, leaving some space between each cookie.
Press down slightly on each dough ball and press a few extra “kitchen sink bits'' on top of each cookie. Finish with a sprinkle of flaky sea salt on top of each cookie.
Bake the cookies in the preheated oven for 12-14 minutes, or until the edges are golden brown. (baking times may vary depending on the size you scoop your cookies)
Once baked, remove the cookies from the oven and let them cool on the baking sheet for 2-3 minutes before transferring them to a wire rack to cool completely.