Slack Meme Bot - Spice up your team conversations with memes
GitHub Visualizer - Enter user/repo and see the project visually
GoGifApp - Free Slack GIFs App, multiple images to pick from at once
Gource - Gource is a software version control visualization tool.
VixT on Slack - The best video mashup app now on Slack.
CodeFlower - CodeFlower visualizes source code repositories using an interactive tree.