Danka or Dana
Danuta seems relatively rare now.... back when there were more Danka seemed the go to abbreviation (Danusia in a respectable second). I don't remember ever hearing Dana... it must have happened but not often enough for me to notice (or my Polish wasn't good enough to notice then).
One of the (many, many, many) bad things about 'zdalne' nauczanie is not getting to overhear students. I remember an academic talk by a professor of Polish/linguistics that was largely based on forms he'd overheard in the halls...
Polish wiki indicates that Danuta is probably of Lithuanian origin "sky-daughter" or Latin(?) "given (by God)"...
