In Vedic literature, Devas and Devis represent the forces of nature and some represent moral values (such as the Adityas, Varuna, and Mitra), each symbolizing the epitome of a specialized knowledge, creative energy, exalted and magical powers (Siddhis).
Vedic era deities evolved over time. Rudra (left) is represented in Vedic literature, is shown as Shiva-Rudra 2nd-century sculpture (middle), and as Shiva (meaning kind) in 13th-century art work (right). The iconography evolved, retaining some symbolic elements such as trident, axe or antelope.The most referred to Devas in the Rigveda are Indra, Agni (fire) and Soma, with "fire deity" called the friend of all humanity, it and Soma being the two celebrated in a yajna fire ritual that marks major Hindu ceremonies. Savitr, Vishnu, Rudra (later given the exclusive epithet of Shiva), and Prajapati (later Brahma) are gods and hence Devas.The Vedas describes a number of significant Devis such as Ushas (dawn), Prithvi (earth), Aditi (cosmic moral order), Saraswati (river, knowledge), Vāc (sound), Nirṛti (destruction), Ratri (night), Aranyani (forest), and bounty goddesses such as Dinsana, Raka, Puramdhi, Parendi, Bharati, Mahi among others are mentioned in the Rigveda. Sri, also called Lakshmi, appears in late Vedic texts dated to be pre-Buddhist, but verses dedicated to her do not suggest that her characteristics were fully developed in the Vedic era. All gods and goddesses are distinguished in the Vedic times, but in the post-Vedic texts (~500 BCE to 200 CE), and particularly in the early medieval era literature, they are ultimately seen as aspects or manifestations of one Brahman, the Supreme power.
Who are the  most referred to Devas in the Rigveda as per the passage?
Indra, Agni (fire) and Soma