There are -
pañcakam (comprising five ślokas),
ṣaṭkam (comprising six ślokas),
aṣṭakam (comprising eight ślokas),
śatakam (with a hundred ślokas),
sāhasrī (with a 1,000 ślokas).
Nirvāṇaṣaṭkam is a ṣaṭkam.
Rarely some of them sometimes contain long compounds leaning towards artificiality, especially when the subject matter is Tantric.
Some of such examples are -
Kanakadhārā-Stotra,
Mahiṣāsuramardinī-Stotra,
Saundaryalaharī.
आत्मा त्वं गिरिजा मतिः सहचराः प्राणाः शरीरं गृहं
पूजा ते विषयोपभोगरचना निद्रा समाधिस्थितिः ।
सञ्चारः पदयोः प्रदक्षिणविधिः स्तोत्राणि सर्वा गिरो
यद्यत्कर्म करोमि तत्तदखिलं शम्भो तवाराधनम् ॥
-शिवमानसपूजा 4
The later the stotra, less is its merit.
A highly popular Mahiṣāsuramardinī-Stotra, contain anomalies & blunders in grammar & metre.
There are works of the Aḷwars (Tamil),
Vidyāpati (Maithili),
Tulasidās (Avadhi),
Suradās (Braja Bhasha),
Mirābai (Rajasthani and Braj Bhāshā),
Kabir ( Hindi, borrowing from various dialects including Avadhi, Braj, and Bhojpuri),
Jnāneswar (Marathi),
Tukāram (Marathi),
Narsimhadas Mehta (Gujarati),
Purandara Dāsa (Kannada),
Tyāgarājā (Telugu and Sanskrit),
Jagannātha Dāsa (Odia ),
are high class hymnologists.
(Excerpts from my forthcoming book
"Hymnology - Suktas and Stotras")