I've read many differing stories, but exactly what Astras did Indrajit know how to use?
To be really honest, it is very broad and long to name all the weapons which Indrajit knows how to use, but I will try to mention some of his most potent skills and powers as mentioned in Valmiki Ramayana. In Yuddhakanda chapter 80,
Indrajit obtains a capacity of going out of sight while fighting, and he did so during his battle with Rama and Lakshmana.
स तु वैहायसं प्राप्य सरथो रामलक्ष्मणौ |
अचक्षुर्विषये तिष्ठन्विव्याध निशितैः शरैः [6-80-3]
Meaning: Indrajit with his chariot, reaching the sky and remaining invisible, struck Rama and Lakshmana with his sharp arrows.
Beside arrows as mentioned in above verse, Indrajit was capable of using missiles.
रावणिस्तु दिशः सर्वा रथेनातिरथः पतन् |
विव्याध तौ दाशरथी लघ्वस्त्रो निशितैः शरैः [6-80-33]
Meaning:Indrajit for his part, who was a superior chariot-warrior and who was swift in discharging missiles, rushed on towards all sides and pierced Rama and Lakshmana with his sharp arrows.
Indrajit also know how to use sword. During his battle in war with Hanuman, he created an illusory image of Seetha, and killed her.
तमेवमुक्त्वा रुदतीं सीतां मायामयीं ततः ||
शितधारेण खड्गेन निजघानेन्द्रजित्स्वयम् | [6-81-29]
Meaning :Having spoken thus to Hanuma, Indrajit personally killed that illusory Seetha, who had been sobbing all the while, with his sharp-edged sword.
He is a great astradhari. He knows the knowledge of many astras including that of the three ultimate weapons of the trimurti's Brahmanda Astra, Vaishnava Astra and the Pashupat Astra. Source : https://en.wikipedia.org/wiki/Indrajit.
Indrajit played an active role in the great war between Rama and Ravana. He is considered as the only Atimaharathi class warrior ever born on earth as told in the Ramayana, Mahabharata, Puranas and the Vedas. He is one and only warrior who possessed the three ultimate weapons of Trimurti, i.e. Brahmanda astra, Vaishnavastra, and Pashupatastra. He acquired all kinds of celestial weapons from his Guru Shukra, Lord Brahma, Vishnu and Shiva. By defeating the Devas in the heaven he took their weapons and become the possessor of all kinds of divine weapons of deva, asura's and trimurti's. Indrajit subdued both Rama and Lakshman, and later incapacitated Lakshman in their second encounter. Indrajit killed 670 million Vanara's in a single day, nearly exterminating the entire half man-half monkey
Not even Trimurtis Lord Brahma, Vishnu and Shiva possessed the ultimate weapons of their contemporaries. Indrajit was trained under the guidance of Shukra and obtained all kinds of divine weapons of man, Devas, Asura's and Trimurti's. The weaponry is categorized mainly into two types. One is Shastra, a handheld weapon like sword, lance or mace. The other is astra, a projectile missile invoked by reciting hymns.
Meghanada was also an expert in magical warfare, sorcery and tantra. He was married to Sulochana, the virtuous daughter of the King of the Serpents, Shesha Naga
he fought fiercely and arrested both the brothers using his most nefarious weapon Nagapash (a trap made of a million snakes). Both the brothers fell on the ground breathless. They were rescued by Garuda on behest of Hanuman
Seeing his uncle Vibhishana at Lakshmana's side multiplied Indrajit's fury manyfold. He vowed to kill his uncle Vibhisana along with Lakshmana once and for all, letting loose the Yama-astra which he had been conserving for punishing Vibhishana's perceived treason.
tena viireNa tapasaa varadaanaatsvayaMbhuvaH | astraM brahmashiraH praaptaM kaamagaashcha turaMgamaaH || 6-85-12
"By his penance, Indrajit obtained a weapon called Brahmashira, by way of a gift from Brahma and also horses, which are coursing at his will."
He proceeds to the battle-field and releases a flood of arrows towards Rama and Lakshmana, while himself remaining invisible in the sky. With a network of arrows, Indrajit creates a darkness in the sky and showers a multitude of steel arrows towards Rama and Lakshmana. Sharp golden shafts arrows are then released by Rama and Lakshmana. Struck by the arrows discharged by Indrajit, monkeys in hundreds fall down dead
While Hanuman and his army are watching, Indrajit pulls Seetha by her hair and unsheathed his sword. Indrajit kills the illusory living image of Seetha, with his sharp sword. Lakshmana informs Vibhishana that on hearing the words of Hanuma saying that Seetha was killed by Indrajit, Rama fell into a swoon. Telling Rama the secret of conjuring trick practiced by Indrajit in killing an illusory image of Seetha, Vibhishana assures him of Seetha being still alive
Indrajit is one of the best warrior and considerd as Ati-Maharathi in Ramayana. In Ramayana war He had defeated Laxmana twice and Lord Shri Rama Once. I will try to list some of the Astra's used by Indrajit in Ramayana war
2. Lakshmana and Indrajita last battle:- Here indrajita used many astra's against laxmana. at the beginning of battle, Indrajit used Lord Yama's weapon. in the same battle he used **
These are the weapons indrajit used in Ramayana war. But apart from these weapons Indrajit has
in his Armour.