Examples of methods that you will find useful sooner or later of the Slack API using the slack-ruby-client.
- emoji.list: i would say the only possible use for this is spam, but can probe useful is you want something like the URL.
- reactions.add: reacting like there's no tomorrow, but you need the timestamp of the message.
- search.files: for using this method you need to use an user token.
- users.list: you can get all the user info that is accessible.
- Enseñandole a un bot a ser como tú: i explain how to get your user token and how methods work but in spanish.