What expense category are etsy listing fees reported under?

You can choose the business expense that best fits the business purpose/reason for your particular situation. You might list them under:  

• Advertising because Etsy is essentially an advertising platform for your products, or 
• Commissions because it is a percentage of your sales, or 
• Miscellaneous but I like to use this sparingly (it shouldn't be a large portion of your expenses)
  
• Note: Supplies is a common category for anything that's specific for your business

As long as you report your actual expenses, there's no penalty for choosing the incorrect category. Just choose the one that best describes the nature of your expenses.