The file type for both folders & files/assets are different.
You can create some custom code(maybe using JS) that reads the number of assets on a page/in crx and adds button to them using JS with DOM.
You can get all the assets on the page and append the button to them using a loop or something like that.
On a page, the assets are basically enclosed in anchor tags which when clicked direct us to the clicked asset.
Ex:
let btn = document.createElement("button");
btn.className = "<bla bla bla>";
btn.appendChild(document.createTextNode("<bla bla bla>"));
EachAsset.appendChild(btn);