@jonathanmh I use exactly what you've described and it is immensely useful.
People select a topic prefix (badge) from a dropdown menu (could autocomplete with NodeBB when typing the post title). The options are preconfigured from the ACP (in my case things like Mix, Tutorial, Q&A, Sample) clicking these while in a category filters only those with matching prefixes (badges). It's great for busy forums where people only want to see certain things rather than scanning through page after page of posts. (In a way it's similar to the Mark as Read that's already implemented where it filters by category. But for posts.
+1 for this.