I want to know who are the seven sages (Sapta Rishis) of current Manvantara?
The Sapta Rishis of the present Vaivasvata Manvantara are described in this chapter of the Srimad Bhagavatam:
The present Manu, who is named Śrāddhadeva, is the son of Vivasvān, the predominating deity on the sun planet. Śrāddhadeva is the seventh Manu. Now please hear from me as I describe his sons. O King Parīkṣit, among the ten sons of Manu are Ikṣvāku, Nabhaga, Dhṛṣṭa, Śaryāti, Nariṣyanta and Nābhāga. The seventh son is known as Diṣṭa. Then come Tarūṣa and Pṛṣadhra, and the tenth son is known as Vasumān. In this manvantara, O King, the Ādityas, the Vasus, the Rudras, the Viśvedevas, the Maruts, the two Aśvinī-kumāra brothers and the Ṛbhus are the demigods. Their head king [Indra] is Purandara. Kaśyapa, Atri, Vasiṣṭha, Viśvāmitra, Gautama, Jamadagni and Bharadvāja are known as the seven sages. In this manvantara, the Supreme Personality of Godhead appeared as the youngest of all the Ādityas, known as Vāmana, the dwarf. His father was Kaśyapa and His mother Aditi.
The Sapta Rishis are: Kashyapa, son of Brahma's son Marichi's and father of numerous beings, including Indra as I discuss here; Atri, mins-born son of Brahma and father of Chandra, Dattatreya, and Durvasa as I discuss here; Vasishta, who was originally the son of Brahma but later became the son of Mitra and Varuna, as I discuss here; Vishwamitra, the irritable king-turned-sage who took Rama to the forest and gave him weapons; Gautama, husband of Ahalya whom Rama saved, and originator of the Godavari river as I discuss here; Jamadagni, father of Vishnu's incarnation Parashurama; and Bharadwaja, son of Brihaspati and adopted son of the great king Bharata whom India is named after, as I discuss here.
So unlike in the Swayambuuva Manvantara, most of the Sapta Rishis in the current Vaivasvata Manavantara are not mind-born sons of Brahma.