Since ancient times 108 has been considered a sacred number in Hinduism. There are various views about what is the significance of the number 108? Some say that there are 108 names for each deity and others hold that these are 108 paths to reach to god etc.
But that is not the topic of our discussion - we can see a related post about 108 beads in the rosary on Hinduism Stack Exchange.
So continuing our discussion about your query whether Ashtottara Shatanamavali is just 108 names of respected god/goddess or will have some Phala Sruti (rewards ) for every ashtottara shatanamavali?
Ashtottara Shatanamavali means collective hundred and eight names of God or Goddess. We find many Ashtottara Shatanamavalis in Purana as well as in epics like Mahabharata. These names are composed by Rishis, devotees, divine beings etc.
But are these just names of gods or goddesses? No, if we observe carefully we can see that these names are very special and these names are associated with detailing of the qualities of god/goddess. Generally 108 names of deities denotes following points - Physical appearance , forms ,special deeds , characteristics , merits , and to what the particular god or goddess is associated ( e.g. wisdom , power ,wealth ) , what is the Vahana vehicle , special mythological incident related , the role, special powers, flags, holding type of weapons, son/daughter/husband /wife of, dressing and ornaments wearing, demons slain etc.
So the names in Ashtottara Shatanamavalis mentions the points like above and hence they are also unique to god/goddess sometimes.
Let's see few examples of above points from various Ashtottara Shatanamavalis -:
Ashtottara Shatanamavali of Lord Shiva
कपर्दी - Kapardi -ॐ कपर्दिने नमः। -Om Kapardine Namah।- The Lord With
Thickly Matted Hair.
Ashtottara Shatanamavali of Goddess Saraswati.
वाग्देवी -Vagdevi -ॐ वाग्देव्यै नमः। -Om Vagdevyai Namah। -The One Who
is the Goddess of Speech.
हंसासना -Hamsasana-ॐ हंसासनायै नमः।-Om Hamsasanayai Namah।-The Goddess
Whose Seat is of Swan.
Ashtottara Shatanamavali of Kartikeya.
शिखिवाह -Shikhivahan -ॐ शिखिवाहनाय नमः। -Om Shikhivahanaya Namah।
-Hail to the rider on the peacock
These Ashtottara Shatanamavalis are found in various Hinduism scriptures and generally, there is a story related to every namavali i.e. these garland of collection of 108 names are recited by various persons in praise of deities on some special occasions and are part of mythological narrations or stories. Although some are also independent with no association with scriptures and are composed by various sages. We can say that these are hymns of various deities.
There is an Ashtottara Shatanamavali of Lord Surya (Sun God) present in Mahabharata -Vana Parva -Aranya Parva-Chapter 123.
"Vaisampayana said, 'Listen attentively, O king, purifying thyself and
withdrawing thy mind from every other thing. And, O king of kings,
appoint thou a time. I will tell thee everything in detail, And, O
illustrious one, listen to the one hundred and eight names (of the
sun) as they were disclosed of old by Dhaumya to the high-souled son
of Pritha. Dhaumya said, 'Surya, Aryaman, Bhaga, Twastri, Pusha, Arka,
p. 10 Gabhastimat, Aja, Kala, Mrityu, Dhatri, Prabhakara, Prithibi,
Apa, Teja, Kha, Vayu, the sole stay, Soma, Vrihaspati, Sukra, Budha,
Angaraka, Indra, Vivaswat, Diptanshu, Suchi, Sauri, Sanaichara,
Brahma, Vishnu, Rudra, Skanda, Vaisravana, Yama, Vaidyutagni,
Jatharagni, Aindhna, Tejasampati, Dharmadhwaja, Veda-karttri, Vedanga,
Vedavahana, Krita, Treta, Dwapara, Kali, full of every impurity, Kala,
Kastha, Muhurtta, Kshapa, Yama, and Kshana; Samvatsara-kara, Aswattha,
Kalachakra, Bibhavasu, Purusha, Saswata, Yogin, Vyaktavyakta,
Sanatana, Kaladhyaksha, Prajadhyaksha, Viswakarma, Tamounda, Varuna,
Sagara, Ansu, Jimuta, Jivana, Arihan, Bhutasraya, Bhutapati, Srastri,
Samvartaka, Vanhi, Sarvadi, Alolupa, Ananta, Kapila, Bhanu, Kamada,
Sarvatomukha, Jaya, Visala, Varada, Manas, Suparna, Bhutadi, Sighraga,
Prandharana, Dhanwantari, Dhumaketu, Adideva, Aditisuta, Dwadasatman,
Aravindaksha, Pitri, Matri, Pitamaha, Swarga-dwara, Prajadwara,
Mokshadwara, Tripistapa, Dehakarti, Prasantatman, Viswatman,
Viswatomukha, Characharatman, Sukhsmatman, the merciful Maitreya.
These are the hundred and eight names of Surya of immeasurable energy,
as told by the self-create (Brahma). For the acquisition of
prosperity, I bow down to thee, O Bhaskara, blazing like unto gold or
fire, who is worshipped of the gods and the Pitris and the Yakshas,
and who is adored by Asuras, Nisacharas, and Siddhas. He that with
fixed attention reciteth this hymn at sunrise, obtaineth wife and
offspring and riches and the memory of his former existence, and by
reciting this hymn a person attaineth patience and memory. Let a man
concentrating his mind, recite this hymn. By doing so, he shall be
proof against grief and forest-fire and ocean and every object of
desire shall be his.'
Above we can see that a Paashruti (merit, rewards, advantage, benefit, profit. etc.) of recitation of the names is also mentioned.
The second Ashtottara Shatanamavali is from Skanda -Purana
-Vol.2 -Book 1-Maheshwar Kanda -Kumarika Kanda. Here we find 108 names of Lord Kartikeya or Skanda
composed by Rishi Vishvamitra. This Ashtottara Shatanamavali is part of the story of the birth of Skanda and slaying of Mahishasura by him. Same as above we can see the Paashruti here as well.
Page No. 245
123 The holy lord Vishvamitra sought refuge in Kumara. He composed a
divine hymn to Mahasena.
124 It consists of one hundred and eight
names. By repeating them, sins are destroyed and one shall attain
144-147 Fortune will flourish in the family of that person who reads
this regularly. Neither Rakshas nor Pisacas, neither goblins nor
mishaps cause obstacles in that house where they eulogize me thus. He
will not have evil dreams. The person who is bound will be liberated
from bondage. By the power of this hymn (prayer) the man will attain
Conclusion - Although these Ashtottara Shatanamavali are also names, they are of special type denoting qualities. The no. 108 is probably because there are 108 beads in a rosary. These 108 names are composed as a prayer to various deities on special occasions by various persons generally to find a solution to problems or to seek the help of the deity, thus they hold special importance. A devotee can also make use of these names and can solve his various problems of life or just chant them for devotion, this is the actual purpose of them and that is why they are part of scripture so that a devotee can also get benefited from them. And from the above two examples is clear that these Ashtottara Shatanamavali found in Puranas, epics etc. normally contain Phalashruti.
Ashtottara Shatanamavali of various Hindu Gods