I have built an AutoMod bot for my instance, lemmy.basedcount.com. The bot covers the following features:

• Automated removal
  • of posts, based on their title, content or link
  • of comments, based on their content
  • configurable with either regular expressions or substrings
• User whitelisting and exceptions for moderators to selectively lift some or all of the aforementioned rules for certain users.
• Mention based pinning and locking of a post, through commands exclusively available to the mod team
• Discord notifications for new registration applications through a webhook. [only for admins]

Naturally, the bot is completely open source. I have also written a rather comprehensive (albeit long-winded) documentation and some examples.

This project is mainly targeted towards admins of small instances, however anyone can spin up their own AutoMod instance for their favourite community (provided they are a moderator there).
The automoderator is also available as a Docker image, for ease of installation.

Feel free to suggest any additional features that you might want to see added to this bot.