Firesong - Giphy for Music in Slack w/ Emoji Search
Magic Playlist - Get the playlist of your dreams based on a song
Slack Meme Bot - Spice up your team conversations with memes
Spotalike - Spotify playlist with similar songs, according to Last.fm
VixT on Slack - The best video mashup app now on Slack.
Playlist Machinery - Tools that help you create & organize your Spotify playlists