The emoji importer lets you add custom emoji to Linear. Upload individual emoji files or import your Slack emoji by authenticating to your Slack account. When editing a Team, Project, or View, select the icon to change it and then search for or scroll all the way down the list to view your workspace's custom emoji.
Upload emoji individually or import your organization's Slack emoji in settings. Any member can import custom emoji from Slack, they don't have to be an admin in Linear or Slack.