I use BETSI at least once a month to bulk edit. This is such a time saver! What used to take all day, I can do in minutes. I edit tags, titles, descriptions, even images.
I also love FotoFuze to brighten up my pictures. It makes a plain white background super bright white and makes your photos pop! You just have to be sure to keep the shadows in your images to avoid the product looking like it is "floating".
Another app I really like is Outright. I linked my Etsy shop, PayPal account, and bank account so it is easy for me to keep track of income and expenses. It does everything automatically for you, but you can add, delete, and edit.