The first rotating Crumbl Cookie flavors were the week of June 11-16, 2018. The first flavors were:
1. NUTELLA SEA SALT
2. OATMEAL CHOCOLATE CHIP
3. REESE’S CHIP
4. CHILLED SUGAR
5. MILK CHOCOLATE CHIP
You can read more about the first few weeks of Crumbl Cookies rotating flavors and how it became a thing here.