Slack Workspace Theme Customization
How to customize your slack theme
SlackThemes.net
AJonP is not sponsored by Slack , neither is slackthemes.net at time of this posting. But we both think it is a great tool!
Fork SlackThemes Repo
If you make a cool theme add it to paracycle/slackthemes GitHub repository. It is as simple as making a pull request.Fork a repo - GitHub Help