Mantras of various deities

Now a days there are thousands of mantras available in all kinds of remedial books and magazines. The authenticity and the effectiveness of most of them are quite doubtful. Most of what we are reproducing below is from the book "Meditations from the Tantras" by Paramahamsa Swami Satyananda Saraswati, one of the greatest self realized yogis of our times and an acknowledged master of the tantra.

Gayatri Mantra: According to the Hindu scriptures Devi Gayatri is the Mother of the Vedas. It is said that even Trinities (Brahma, Vishnu and Shiva) worship her as their Mother.
The Gayatri Mantra is the prescribed daily mantra for all Hindus and regarded as the remover of all sins and the bestower of all desired things. It is also part of the Sandhya Vandana.
The sage Vishwamitra is given the credit for bringing Mother Gayatri to earth. The following is the most commonly recited Gayatri Mantra.
Om Bhuh Bhuvah Svah Tat Saviturvarenyam
Bhargodevasya Dhimahi Dhiyoyonah Prachodayat

The meaning of the Gayatri mantra is as follows:
We contemplate the glory of Light illuminating the three worlds: gross, subtle, and causal. I am that vivifying power, love, radiant illumination, and divine grace of universal intelligence. We pray for the divine light to illumine our minds.
Om: The primeval sound
Bhur: the physical world
Bhuvah: the mental world
Suvah: the celestial, spiritual world
Tat: That; God; transcendental Paramatma
Savithur: the Sun, Creator, Preserver
Varenyam: most adorable, enchanting
Bhargo: luster, effulgence
Devasya: resplendent, supreme Lord
Dheemahi: we meditate upon
Dhiyo: the intellect, understanding
Yo: May this light
Nah: our
Prachodayath: enlighten, guide, inspire
The other Gayatri Mantra is as follows:
Om Bhu, Om Bhuvah, Om Svaa, Om Mahaa, Om Janah,
Om Tapah, Om Satyam, Om Tat Savitur Varenyam Bhargo
Devasya Dhimahi Dhiyo Yo Nah Prachodayat
Om Apo Jyotih Raso-mritam Brahmaa Bhur Bhuvah Swaa Om
According to the Hindu belief there are fourteen worlds. Bhu, Bhuvah, Svaa, Mahaa, Janah, Tapah, Satyam are the seven Higher worlds and Atata, Kutala, Vitala, Mahatala, Rasatala, Bhutala and Patala are the seven Lower worlds. The above Gayatri mantra is recited by those seeking the higher worlds.
Maha Mrituyunjaya Mantra: This mantra of lord Shiva is the most effective and the most commonly recited one for curing all types of illnesses and to avoid any misfortunes and untimely death.
Om Tryambakam Yajamahe Sugandhim Pushti Vardhanam
Urvaarukamiva Bhandanath Mrityor Muksheeya Mamritat

Vedic Gayatri Mantras of other Gods :
Ganesh: Om Ekadantaya Vidmahe Vakratundaya Dhimahi Tanno Danti Prachodayat
Vishnu: Om Narayanaya Vidmahe Vasudevaya Dhimahi Tanno Vishnu Prachodayat
Narasimha: Om Vajranakhaya Vidmahe Mahadevaya Dhimahi Tanno Narashimha Prachodayat
Rudra: Om Tat Purushaya Vidmahe Mahadevaya Dhimahi Tanno Rudrah Prachodayat
Lakshmi: Om Mahadevyai Cha Vidmahe Vishnu-patnyai Cha Dhimahi Tanno Lakshmi Prachodayat
Kartikeya: Om Tatpurushaya Vidmahe Mahasenanaya Dhimahi Tanno Shanmukha Prachodayat
Other Kartikeya mantra: Om Saravanabhavaya Namah
Sasthi and Chaturdasi are the best tithis to worship Krtikeya.
Santana Gopala mantra: For those having difficulty in begetting children, reciting the following Santana Gopala mantra and worship of Lord Krishna in a child form is an excellent remedy.
Devakisutam Govindam Vasudevam Jagatpatim
Dehime Tanayam Krishna twam-aham Sharanagatah.

Siva Mantras:
1. Om Namah Sivaya
2. Om Haraye Namah
3. Om Tryambakam yajamahe sugandhim pushtivardhanam
Urvarukamiva bandhanat mirityormurkshiya mamaritat
4. Om Namah Nilakanthaya
5. Hroum
6. Proum Hrim thah
7. Ram ksham mam yam oum um

Vaishnava Mantras:
1. Om Narayanaya namah
2. Om Vishnave namah
3. Om Vishnave parjyotye namah
4. Om Paramatmane namah
5. Om Anantaya namah
6. Om Achyutaya namah
7. Om Govindaya namah
8. Om Achyutananta Govindaya namah
9. Om Klim Hrishikeshaya namah
10.Om Shri Shridharaya namah
11.Om Shri Madhusudayanaya namah
12.Om Damodaraya namah
13.Om Namo Narayanaya namah
14.Om Shri Mannarayana-charanou-sharanam prapadye
Shri Rama Mantras:
1. Om Shri Rama jaya Rama jaya jaya Rama
2. Om Shri Ramaya namah
3. Om Shri Sitaramachandrabhyam namah
4. Ramaya Ramabhadraya Ramachandraya Vedhase
Raghunathaya nathaya Sitayah pataye namah
5. Om Shri Ramah sharanam mama
6. Om Shri Shri Sitaramah sharanam
7. Om Ramachandra-charanou-sharanam prapadye
8. Ram Ramaya namah
9. Ham so Ramaya namah soaham
10.Hrim Ramaya namah hrim
11. Hroum Ramaya namah hroum
12. Aim Ramaya namah
13. Klim Ramaya namah
Krishna Mantras:
1. Om Namo Bhagavate Vasudevaya
2. Om Shri Krishnaya Govindaya Gopijana-vallabhaya namah
3. Om Shri Krishnaya namah
4. Om Shri Krishanh sharanam mama
5. Klim
6. Krishnah
7. Klim Krishnayah
8. Klim Krishnayah Govindaya klim

Shakti Mantras:
Kali:
1. Hrim Shrim Krim Parameswarayai svaha
2. Hrim Shrim Krim Parameswari Kalike hrim shrim krim svaha
3. Om Shri Kalikayai namah
4. Om Hrim me svaha )Kali Hridaya)
5. Krim Krim Krim Hum Hum Hrim Hrim dakshine Kalike Krim Krim Krim Hum Hum
Hrim Hrim svaha
6. Krim Hrim Shrim

Durga:
1. Om Shri Durgayai namah
2. Om Hrim Dum Durgayai namah

:

Saraswati:
1. Om Shri Saraswatyai namah
2. Om Hrim Aim Hrim Aum Sarasvatyai namah

Mahalakshmi:
1. Hrim Shrim Krim Mahalakshmayai namah
2. Om Shrim Hrim Kamale Kamale Kamalalaye prasida prasida Shrim Hrim Shrim Mahalakshmyai namah

Radha:
1. Om Shri Radhayai Svaha
2. Om Hrim Radhikayai namah

Annapurna:
Hrim namo bhagavati maheswari Annapurne svaha
Indrakshi:
Om Shrim Hrim Krim Aim Indrakshyai namah
Chamunda:
Om Aim Hrim Krim Chamundayai Vichche

Siddha Mantras of Hanuman for power and siddhis:

The Hanuman mantras are very effective for all Saturn related problems, for health, to avoid and overcome troubles caused from enemies and to avoid imprisonment.
1. Om Hanumate namah
2. Om namo bhagavate anjaneyaya mahabalaya svaha
3. Om Hanumate rudratmakaya hum phat
4. Om Pavana nandanaya svaha

5. Om Namo bhagavate anjaneyaya amukasyashrinkhala trotaya trotaya bandha moksham kuru kuru svaha

6. Purvakapimukhaya panchamukha haumate tam tam tam tam tam sakala shatru shanharanaya svaha
7. Om pashchimamukhaya garudananaya panchamukha hanumate mam mam mam mam sakala vishahara svaha

8. The powerful Vedic Pooja/Homa mantra of Hanuman is as follows:
Om Aim Hreem Shreem

Hanumate Ramadootaya

Lanka vidhwamshanaya

Anjana garbha sambhootaya

Kila kila bhoo bhoo karine Vibheeshanaya

Hanuma devaya

Om Aim Hreem Shreem Hram Hreem Hrom Phat Swaha