There are several forms of Narasimha, but 9 main forms are known as Nava Narasimha.
1) Ugra Narasimha
2) Kroddha Narasimha
3) Vira Narasimha
4) Vilamba Narasimha
5) Kopa Narasimha
6) Yoga Narasimha
7) Aghora Narasimha
8) Sudarsana Narasimha
9) Laksmi Narasimha
The Nine forms of Narasimha in Ahobilam temple are as follows:
1) Chatra Vata Narasimha (seated under a banyan tree)
2) Yogananda Narasimha (who blessed Lord Brahma)
3) Karanja Narasimha
4) Uha Narasimha
5) Ugra Narasimha
6) Krodha Narasimha
7) Malola Narasimha (With Lakshmi on his lap)
8) Jvala Narasimha (an eight armed form rushing out of the pillar)
9) Pavana Narasimha (who blessed the sage Bharadvaja)
Forms of Narasimha from Prahlad story:
1) Stambha Narasimha (coming out of the pillar)
2) Svayam Narasimha (manifesting on his own)
3) Grahana Narasimha (catching hold of the demon)
4) Vidarana Narasimha (ripping open of the belly of the demon)
5) Samhara Narasimha (killing the demon)
The following three refer to his ferocious aspect:
1) Ghora Narasimha
2) Ugra Narasimha
3) Canda Narasimha
Others forms of Narasimhas:
1) Pancamukha Hanuman narasimha, (appears as one of Sri Hanuman’s five faces.)
2) Pruthvi Narasimha, Vayu Narasimha, Akasa Narasimha, Jvalana Narasimha, and
Amrta Narasimha, (representing the five elements)
3) Jvala narasimha (with a flame like mane)
4) Laksmi narasimha (where Laksmi pacifies Him)
5) Prasada/Prahlada varada narasimha (His benign aspect of protecting Prahlad)
6) Chatra narasimha (seated under a parasol of a five hooded serpent)
7) Yoga Narasimha or Yogesvara Narasimha (in meditation)
8) Avesa Narasimha (a frenzied form)
9) Attahasa Narasimha (a form that roars horribly and majestically strides across to destroy evil)
10) Cakra Narasimha, (with only a discus in hand)
11) Visnu Narasimha, Brahma Narasimha and Rudra Narasimha
12) Pusti Narasimha, (worshipped for overcoming evil influences)