If you still need some ideas for new products then have a think outside of your usual product lines. Do you know on Etsy you can sell Vintage Items, Handmade Products, or Craft Supplies? With the launch of the New Etsy Studio Craft Supplies Website (https://www.etsy.com/seller-news/introducing-etsy-studio) now might be a good time to think if you can add any craft kits or items to your store!
See here for some suggestions for what to sell in your Etsy shop: https://www.etsy.com/seller-handbook/article/what-to-sell-on-etsy/67553338536. If you're worried that you are going to end up with too many craft supplies to store, or too many things to post, then what about considering digital downloads? Click here for some tips on how to get started and what kind of things you might be able to sell digitally: https://www.etsy.com/uk/seller-handbook/article/how-to-sell-digital-downloads-on-etsy/47330319230.
In the EU customers have to pay 20% VAT on digital goods, but Etsy very helpfully collect it and pay it for us - they add 20% onto whatever price you say you'd like to receive and then collect that 20% to pay the government. Here's more information on that: https://www.etsy.com/uk/seller-handbook/article/etsys-new-collection-process-for-value/26557870596
What ever new items you add, make sure they fit with your brand (or open a new shop with a new brand if you can't get the idea out of your head!). And make sure it's something people will want to buy!