I’m so sorry about the delay in response. I was out of town most of January due to a family emergency and when I got back I went straight into catching up on stuff for my shop. I’m so sorry!
I’m not sure I completely understand your question though. I think most shops go in and add those dots themselves, so I’m not sure about the confetti overlays on Etsy. I have a feeling (at least from what I’ve seen from other shops) most of them are just creating that and using the layers tool to add it over the sticker. Hopefully that makes sense.
If I hear of anything different I’ll let you know, but I’m pretty sure they are just adding a bunch of dots themselves and it’s not a confetti overlay found on Etsy. However I could be wrong on that.