مُسْلِمَاتٌ and طَالِبَاتٌ are common sound feminine plurals.
But the ending «ات» alone is not proof. For example, بَيْتٌ ← أَبْيَاتٌ changes the internal plural pattern, so أَبْيَاتٌ is a broken plural.
رَأَيْتُ أَبْيَاتًا.
Translation: I saw several lines of poetry.
Here أَبْيَاتًا is accusative with fatḥa. It does not follow the sound feminine plural rule merely because the spelling ends in «ات».