There are many asura's who fought God in purans but is there any mention of asura's fighting God in vedas.
There are some places in Vedas where Indra is shown as killer of asuras.
In Rigveda 6:26:3 It is written that Indra killed a demon called susna.
Rig Veda 6.26.3 Thou didst impel the sage to win the daylight, didst ruin Śuṣṇa for the pious Kutsa.The invulnerable demon’s head thou clavest when thou wouldst win the praise of Atithigva.
Indra also killed a demon Namuchi.
Rig Veda 8.14.13 With waters’ foam thou torest off, Indra, the head of Namuci, Subduing all contending hosts.
Rigveda 5:30:7. Thou, Maghavan, from the first didst scatter foemen, speeding, while joying in the milk, the Giver. There, seeking man's prosperity, thou torest away the head of Namuci the Dasa.
In Rigveda 1:7:7 Indra killed Yatudhana.
Rigveda 1:7:7. O Agni, bring thou hitherward the Yātudhānas bound and chained. And afterward let Indra tear their heads off with his thunder- bolt.
Beside Indra, Agni is also said to burn the demons.
Rigveda 2:23:14. Burn up the demons with thy fiercest flaming brand, those who have scorned thee in thy manifested might. Show forth that power that shall deserve the HYMN of praise: destroy the evil speakers, O Brhaspati.
Yajurveda 13:13. Rise, Agni, drive off those who fight against us: make manifest thine own celestial vigour. Slacken the strong bows of the demon-driven: destroy our foemen whether kin or stranger. I settle thee with Agni's fiery ardour.
Agni also kill dasytis.
Rigveda 7:6:3. The foolish, faithless, rudely-speaking niggards, without belief or sacrifice or worship,- Far far sway hath Agni chased those Dasytis, and, in the cast, hath turned the godless westward.
Battles between devas and asuras are described or at least referred to in the Rig Veda. However, we should take care to note that the Vedic asuras are divided between the benevolent Ᾱdityas (led by the Vedic Varuṇa) and the negative Dānavas (led by the Vedic Vṛtra). The main examples are as follows -
The elements of the famous battle between the deva Indra and the asura (Dānava) Vrtra are described in various passages of the Rig Veda such as RV1.32 and RV4.18 etc. (which I assembled into a joined-up narrative here).
The deva Indra and the asura (Ᾱditya) Namuci were allies, but Indra later killed Namuci. The incident is referred to in RV8.14, but the full story is only told in later texts like Śatapatha Brāhmaṇa and Mahābhārata. (I retold it here.)
If we are to include Samhita texts, the story of the battle between devas and asuras is told in the Taittirīya Samhita of the Krishna Yajur Veda. This seems to be the basis for the samudra-manthana events described in the later Bhāgavata Purāṇa).