Snippet of code for the Obsidian extension Dataview, to show all the notes grouped by unique tags.

notes_by_tag.js

```dataviewjs
// Fetching unique tags
let tags = [] 
for (let tag of dv.pages('"notes"').file.tags) {
	if (tags.indexOf(tag) == -1) { 
	tags.push(tag) 
	} 
}
// Table for each tag
dv.header(5,"Notes by tag:")
for (let tag of tags) {
	dv.header(4, tag.substring(1));
	dv.table(["name","created"],
		dv.pages('"notes"').where(p => p.file.tags.includes(tag))
			.map(k => [k.file.link, k["created"]]))
	
}
// List of unique tags
dv.header(5,"Tags:")
dv.list(tags)
```