Upanishads
The Brihadaranyaka Upanishad says there are 33 devas in the celestial world, in terms of performance of yagnas. They are eight Vasus, eleven Rudras, twelve Adityas, Indra, and Prajapati, these groups, however, are mentioned already in the Rigved.
- In Sanskrit:
- स होवाच महिमान एवैषामेते त्रयस्त्रिँशत्त्वेव देवा इति कतमे ते त्रयस्त्रिँशदित्यष्टौ वसव एकादश रुद्रा द्वादशादित्यास्त एकत्रिंशदिन्द्रश्चैव प्रजापतिश्च त्रयस्त्रिँशाविति॥ (वृहदारन्यक ६.९)
Read more about this topic: Deva (Hinduism)