Dataview - Obsidian query engine

Dataview is a live index and query engine over your personal knowledge base. You can add metadata to your notes and query them with the Dataview Query Language to list, filter, sort or group your data. Dataview keeps your queries always up to date and makes data aggregation a breeze.
— Dataview

I use dataview mainly to maintenance my Zettelkasten system. Below some useful queries which help me with that.

No tags or small files?

list where length(file.tags) = 0 or file.size < 512
sort file.name asc

No Inbox tag

list where !contains(file.tags, "inbox")
sort file.name asc

Tags List

LIST WITHOUT ID tags
SORT file.tags
FLATTEN tags
GROUP BY tags

Directory properties

TABLE file.frontmatter.directory
Where file.frontmatter.directory