Does anyone know any good module for adding stickers to the products? I need it a lot
Here is the module you need - On Sale + Product Labels by Aheadworks.
All labels appear according to you rules and with your design. So you can implement a rule to any number of products.
It's awesome you can add stickers or labels to highlight discounts for your products like you need. Refer below link for more details
Use Magento product labels by FMEextensions to add labels, stickers, and ribbons to product images.
I am very pleasure to introduce you with Magento 2 Product Label Extension which allows the store owners to add labels on products for any promoting and branding of items in their store.
I hope you get the solution now, if so then give kudos and accept as solution