Emoji Picker is a free extension that lets you copy and use emojis, wherever you want.
Emoji Picker for Chrome, let you copy one or more emojis with a single click. Just click on the one that you want and paste it wherever you want - Slack or WhatsApp message, Tweet etc.
Emojis are sorted by different categories. You can also search the one that you're looking for with convenient search bar.
All the emojis design are taken from an amazing open source project - Openmoji. Check out their website here -https://openmoji.org