I got these on AliExpress.com. I didn’t notice the size of these stickers. I was hoping to put the RetroPie sticker on my Raspberry Pi case, but it’s way too big for it!
Here is the link to the sales page for these stickers. You have to choose which ones you want. They also have a Konami sticker, but it’s the newer logo and not the classic logo, unfortunately. So, I passed. I do want to buy a smaller RetroPie sticker now.