Test it out at: https://npra.github.io/quadtree-helper/
Select the tiles you want to include by clicking on them. Click again to deselect. Press Ctrl+C to copy the currently selected tiles, or click the "Copy tiles" button. Press Ctrl+V to highlight tiles in your clipboard, or click the "Enter tiles" button to get a box you can use to enter tiles.
based on leaflet-spatial-prefix-tree: https://github.com/missinglink/leaflet-spatial-prefix-tree