I ran a check on wp_options table and I found lots of unsolicited RSS content, which points to sites such as WordPress.org and WP Tavern.

This content is taking 75% of space in my database.

I am aware of a few SE questions about how to remove orphan transients that are not removed automatically, but I’d like to know if there is a way to prevent them from getting into my database in the first place.

A Google search does not help.