Gmail without labels -- become archived emails & eat up storage space

Using the below Gmail advance search operators, you can find all the list of emails are WITHOUT any labels (is archived and is in "All Mails" folder.

-(label:your-1st-label OR label:your-2nd-label OR .... label:your-last-label OR from:me OR in:chat)

However, this command operators allow a maximum 20 labels defined in the search command. So, this command is not useful when you have more than 20 labels/folders.

The other way to group all the unlabelled emails into a new label/folder, see the steps below :

1. Create a dummy label and with new name "Dummy1".
2. Go to "All Mail" folder, click Select: All, then click 'Select all XX conversations'. Then, click "Labels" and tick for "Dummy1".
3. Now click each and every of your existing labels/folders in the left navigation panel, and click
4. Once you run through that for all your labels, the only messages remaining in the "Dummy1" folder are those previously unlabelled emails.