You should check out The Playlist Miner. You just enter some search terms like "party" and "drop" and the app will look for all the playlists that are related to what you're searching for. Then you can click a button and it will make a playlist with the top 100 tracks from those playlists. You can even use boolean operators like "OR" and "NOT" to filter/expand your searches. Check out this blog, by one of the founders of the Echo Nest, for more information.