Zelda Classic tilesets are full sets of tiles, combos, sprite configurations, and other things, that can be imported directly into a quest file. It's a good idea to start your quest by importing the tileset that you wish to use, because most tilesets vary so much in layout that importing a new tileset after starting to build a quest is not a very inviting option. If you're looking for tiles to rip into your quest, try a sheet of loose tiles.