I made a post on this some weeks back. Whether it would be through an ‘automod’ bot (ideally not, in my opinion) - or community settings preventing posts from even going out is another matter.

• Automatic removal option to remove posts and/or comments for specific keywords. This would be most useful for automatically removing posts and comments when people slur. Piefed already has a keyword filter for visibility. This could be expanded to community settings. Have it also fire-off a report to the moderators when someone triggers it.
• Automatic URL removal. Allow communities to blacklist specific urls. Useful for politics or news communities that want to negate sources known for misinformation.
• Automatic removal for repeat URL posting. Very useful for politics or news communities to prevent double-posting.
• Make it so a community can set itself up to only accept text posts, video posts, or image posts. This should prevent tedious janitorial cleanup for communities that only allow links, or text posts (the most common two).
• Post Delay Restrictions. Some communities, perhaps not many, might be interested in posting cooldowns for users. So you can only post 1 post every hour, or 2 posts every hour - or whatever the chosen limit is. This would help negate spammers and over-enthusiastic posters flooding a topical community.
• Post Formatting Requirements. This one could be trickier and more effort than most of the others, but setting conditions for the formatting of new posts would be useful.