My nomination goes to my favourite plugin Breadcrumbs!
This plugin is perfect for structuring your notes so you can always find everything back you ever needed. All papers on a certain topic, or topics that are related to it? Easy! All papers from some author? No problem! All restaurants in the city of Utrecht? Just there! Navigating between days and years? Hovering just above your note! And all of this without requiring code blocks in your notes: Just there in the sidebar of Obsidian!
Breadcrumbs is the primary method I use to structure my vault, and I couldn’t be more happy with it.