What are some alternatives?
When comparing Bitmoji for Slack and Slackmojis, you can also consider the following products
Mirror AI - AI that creates personalized content around you/your friends
My Slack Emoji - Turn your team photos into Slack emoji's
Emoji Packs - Import emoji packs into your Slack and other chat apps
Emoji Best - A crowdsourced directory of the best custom emojis 💯
Pictogrify - Generate unique pictograms from any text
Discord Emoji - Iconfinder, but for emoji.