RightGIF - Less noise, better GIFs. A better /giphy for Slack.
Parallel - Listen to music with friends over Spotify at the same time
Firesong - Giphy for Music in Slack w/ Emoji Search
Slackbox - Spotify playlist collaboration through Slack
Slack Meme Bot - Spice up your team conversations with memes
TuneMeet - Chat with people who are listening to the same song