How to filter files with more than "basic" set of tags?

basically, i only use artist, albumartist, album, track, title, composer, year, genre and embedded cover art. how would i go about creating a filter to show me any files than contain any tags besides the ones listed above? i don't know if this matters or not, but it would be ok files don't have all of those, like cover art or composer, i just want files that have anything other than those.

I presume you want to remove any other fields? I don't think I'd bother trying to create a filter expression. Instead, create an action group containing an action to remove everything else. You can run it on the whole library, or portions of it, and it will 'fix' the files.

Action type: Remove fields except
Fields to leave: ARTIST;TITLE;ALBUM;TRACK;YEAR;GENRE;ALBUMARTIST;COMPOSER;PICTURE

(If you do this, make sure you test it thoroughly first on a few different files before applying it to your whole library.)

i would kinda like to see whats in those tags, on the off chance there is something important i need to move to another field or something, but if i don't hear back pretty soon, i will use "Remove fields except"...i can't believe i overlooked that as an option, i have used it on small batches of files in the past. thanks.

you can filter for specific tag fields with PRESENT, for example:
publisher PRESENT
shows you all files which have a PUBLISHER tag field.

you can also combine more fields, for example:
publisher PRESENT OR date PRESENT OR www PRESENT
shows you all files which have a PUBLISHER or a DATE or a WWW tag field.

but i don't know how to filter for "any other fields than ..."

Here is a mp3tag Filter expression line that might work ... except for the %_covers% tag-field.

NOT ("$regexp($regexp($list('~~','~~','=='),'~~(.+?)~~.+?==','$1~~'),'((ARTIST|ALBUMARTIST|ALBUM|TRACK|TITLE|COMPOSER|YEAR|GENRE)~~)',)" IS "")

DD.20120130.1959.CET

Detlev! Where do you have that pretty $list(,,) function from? Can't see it in any of the help files.

Did you not know?
Lyrics aus Datei importieren?

DD.20120130.2254.CET

No, I didn't. Thank you very much!