Indra rules the devas as king of the heavens in Vedic and Puranic tradition.
Source The Rigveda: The Earliest Religious Poetry of IndiaStephanie W. Jamison and Joel P. Brereton
This source names Indra directly: "The sourced Wikipedia account of Indra, covering his Vedic role as king of the gods and the most frequently invoked deity of the Rigveda, his iconography of vajra thunderbolt and Airavata the white..."
Source Indra, Wikipedia
This source names Indra directly: "Indrani, also called Aindri, is one of the Sapta Matrikas, the seven mother goddesses of Hindu tradition, embodying the shakti or divine power of Indra, king of the gods and lord of storms."
Source Matrikas (Wikipedia)
Named as the presiding deity of the lunar mansion Jyeshtha.
Source History of Dharmasastra, Volume VP. V. Kane
Source Brihat Parashara Hora ShastraSage Parashara (attributed)
This source names Indra directly: "identify, humbles their pride and Indra alone comes closest to recognizing what he has encountered."
Source The Upanishads (Sacred Books of the East, vols. 1 and 15)F. Max Muller
This source names Indra directly: "of Kartikeya, Varahi of Varaha, Indrani of Indra and Chamunda of Chandi or Parvati, each riding her parent god's own vahana and carrying his attributes."
Source Matrikas (Wikipedia)
This source names Indra directly: "Indra kills Vritra and releases the waters: the central Vedic myth and the Indo-European dragon-slaying pattern that also underlies the Norse and Greek versions."
Source The Hymns of the Rigveda, translated with a popular commentaryRalph T. H. Griffith
Indra is said to drink it before killing Vritra and releasing the waters, so the sacrifice supplies the strength for that act.
Source The Rigveda: The Earliest Religious Poetry of IndiaStephanie W. Jamison and Joel P. Brereton
This source names Indra directly: "detail for its sandstone Standing Indra, accession 1987.218.12a, b, from Mathura or Ahicchatra in Uttar Pradesh, India, giving its date, dimensions, and the pedestal inscription that names the..."
Source Standing Indra, accession 1987.218.12a, b (The Metropolitan Museum of Art)
Svarga, Realms Svarga is the celestial paradise ruled by the god Indra, where the virtuous enjoy the fruits of good deeds.
Source Encyclopedia of ReligionMircea Eliade (ed.); Lindsay Jones (ed., 2nd ed.)
Source Vishnu PuranaAnonymous
This source names Indra directly: "of Shiva, Kaumari of Kartikeya, Indrani of Indra, Varahi of Varaha and Chamunda, who is her own case, an emanation of the Goddess herself rather than of a male consort."
Source Matrikas (Wikipedia)
In the Rigveda the class is regularly named under Indra, and it forms a triad with the Adityas and the Rudras.
Source Vedic MythologyArthur Anthony Macdonell
Trayastrimsa is the heaven of the thirty three, over which he presides.
Named with Agni as a presiding deity of the lunar mansion Vishakha.
Source History of Dharmasastra, Volume VP. V. Kane
Source Brihat Parashara Hora ShastraSage Parashara (attributed)