By performing Havan with different types of Havidryas with different rules, procedures and mantras, their results are such that they provide different types of Siddhis. Just as there are different medicines, care and treatment methods for different diseases, similarly the use of Yagyas for various purposes is also different. In ancient times, the Yagyas performers knew the detailed procedures of all those rules very well and derived proper benefits from them. It is sad that today that Vedic Yagya-vidya is getting extinct. Now the people who know the mysterious rules of Yagyas are seen to be negligible. Only hints of those rules are available here and there, which are being mentioned below.
It is the duty of those interested in ancient Indian science to do research in a classical and scientific manner for the research of these mysterious rules and present that treasure of ancestors with complete procedure for the welfare of the people.
Today, Patanjali Yogpeeth has, and is doing special work under the guidance and direction of the most revered Yogarishi Swami Ji Maharaj and the most revered Ayurveda Shiromani Acharyashri Ji Maharaj regarding Yagya, which will be a great gift to the world in the times to come.
Below we are presenting a compilation of some rituals and rituals with scriptural proof in relation to Kamya Yagya, through which we will be able to know the precious Siddha knowledge of ancient times and our faith, belief and dedication towards the Yagya will definitely increase and also by using the ritualistic Yagya in the present life, we will be able to get many achievements, benefits and solutions to the problems.
homam tilaghrutai: kuryataham namna tu mantravit. 

ark: palash khadirouhyapaamargoth pippal:..
udumbar shmi durva kushasch samidh: kramat. 
ekaikasyatvasht shatamashtavimshatirev dha..
hotavya madhu sarpibhyam dadhna va payasen va.
saptame tvam samprapte naktam surya sutasyatu..
yagnyen krut matren sarve shavyatyupadrava:.
-bhavi.pu.au.pra. 4au. 114 shlok 32-40

Meaning:- Arka, Palash, Khadir, Apamarg Peepal, Udumber, Shami (Chhonkar), Doov, Kusha, one who knows the mantra should offer these Kushas in the order, in the name of the planets, with the help of sesame seeds and ghee. Perform Havan to each planet one hundred eight times or twenty two times with honey, ghee, curd or kheer. In this way, on the night of the seventh day, perform a havan to Shanischar, the son of Surya. By doing this, all the disturbances subside.
When the sages asked Sut ji to tell us the worship and prestige of Shiva in the Aghor form, then Sut ji said that the worship of Shiva in the Aghor form should be done with rituals and not without rituals.

tathagni pujam vai kuryadyatha puja tathaiv ch.
sahastram va tadartham va shatamashtottaram tu va..
tilairhom: prakatrtavyo dadhimadhvajya sanyute:.
ghritsaktumadhunam ch sarva du:kh pramarjanam..
vyadhinam nashanam chaiv til homastu mutid:.
sahastran maha bhuti: shaten vyadhi nashanam..
-Ling P.A. 49 verses 3-5

Meaning:- Just as it is said to worship Lord Shiva in the Aghor form, Agni should be worshiped in the same way. As will be the worship, so will be the result. Havan of sesame seeds mixed with ghee, honey and curd should be performed one thousand or half five hundred or one hundred and eight times.
Havan performed with Ghritsaktumadhu removes all sorrows and destroys diseases. Sacrifice of sesame seeds gives prosperity. Offering a thousand offerings greatly increases wealth and prosperity. The disease is cured by hundred sacrifices.

Sahastrena fever yati ksheeren juhotiyam.
Trikaalam masmekam tu sahastram juhuyatpayah.
Masen Siddhayate Tasya Maha Saubhagyamuttamam.
Siddhate chabd homen kshaudrajyaddhi sanyutam.
Yavakshirajya homen caste tandulken va.
Beloved Bhagwanisho Haghorah Parmeshwar:..
Dapna Prashtirnripanaam Cha Ksheer Homen Shantikam.
Shanmasanthu ghritam hutva sarva vyadhi vinashanam.
Rajayakshma tilaihonmannashyate vatsaren tu.
Yav Homen Chayushya Ghriten Cha Jayastada.
Sarva kushtha kshayaartham cha madhunaktaishcha tandulai.
Juhuyadayutan nityam shanmasanniyat: always.
-Ling P.A. 49 verses 8-13

Meaning:- Fever is cured by offering a thousand kheer. For a month, one should perform havan with a thousand kheer offerings in all three periods. One attains success in a month and good fortune increases.
By offering kshudra, ghee, curd for a year, one attains success.
By offering havan of barley, kheer, ghee or rice, Lord Shankar is pleased.
By offering havan of curd, kings are strengthened.
By offering havan of kheer, one attains peace. By offering havan of ghee for six months, all types of diseases are destroyed.
By offering sesame seeds for a year, tuberculosis is destroyed. By offering barley, lifespan increases and by offering ghee, one attains victory.
To remove all types of troubles, one should offer havan of rice mixed with honey. For six months, regularly perform havan with a thousand offerings every day.
When the sages asked about Brahma, Daiva and Agnihotra, Sut ji says-
somavare ch lakshmyadinsampadath yajedbudh:.

aajyannen tatha vipram sapatni kanshch bhojayet .29.
kalyadinbhaumavaretu yajet rog prashantaye.
maash mudgadhakeaannen brahmanaanchaiv 
bhojayet .30.
saumyavare tatha vishnum dadhyannen yajedbudh:.
putra mitra kalatradi pushtirbhavati sarvada .31.
aayushyakamo guruvaro devanam pushtisiddhaye. 
upaviten vastren kshirajyen yajed budh: .32.
bhogarth bhruguvaretu yajeddevansamahit:. 
shadrasopetamannam ch dadyat brahman truptaye .33.
strinam ch truptaye tadvaddeyam vastraaadikam shubham. 
apamrutyu hare mande rudradisch yajed budh: .34.
til homenadanen tilannen ch bhojayet. 
itthanyajach vivudhanarogyadi falam labhet.35.

Meaning:- Those who wish for Lakshmi and wealth, should offer Ghritanna Havan on Monday and feed it to Vipra-wife. 29.
For peace of the disease and to control Kaaladi Dosha, Havan should be performed with four seers of Maash (Urad) and Moong and fed to a Brahmin. 30.
By offering curd and food to Lord Vishnu on Monday, Wednesday, Thursday and Friday, son, friend, wife etc. are nourished. 31. 
Those who desire to increase life span, offer sacred thread, clothes, milk and ghee to the gods on Thursday for its nourishment and success. 32. 
For increasing enjoyment, one should offer sacrifice to the gods with a calm mind on Friday and satisfy the Brahmins by feeding them with six tastes. 33. 
To avoid untimely death, Rudra Yagna should be performed by pleasing women with clothes etc. 34. 
By offering sesame and donating sesame and eating sesame, one gets many benefits including health. 35. 
Homattilaghrutadyashcha Dharma Kamartha Mokshadah. Poojamantranpathedyastu free enjoyment.
-Fire. P.U. 21 verse 27
Meaning:- Havan of sesame and ghee etc. gives religion, work, wealth and salvation. Those who recite the mantras of their worship and consume the pleasures of this world go to the divine worlds.
Kadamba Kalika Homadyakshini Sidhyati Dhruvam.

Bandhook Kinshukadini Vasyakarshiya Homayet.
Vilvam Rajyay Lakshmyartham Patlaanchampkanapi.
Padmani Chakravartitve Bhakshya Bhojyani Sampade.
Durva Vyadhivinashaya is done under the control of all beings.
Priyangu Patli Pushpam Chutpatram Jvarantakam.
Mrityunjayo death jitsyaad vriddhi syattilho patah.
Rudrashanti: Sarvashantya atha prasthisht muchyate.
-Agne. Pu.A. 81 Shloka 49-52

Meaning:- By offering havans of Kadamba buds, Yakshini is definitely accomplished. For subduing someone, one should offer havans of Bandhuk Kinshukadi.
For obtaining kingdom, one should offer havans of Bilva fruits. For obtaining Lakshmi, one should offer havans of Patal and Champak. For edible food, wealth and Chakravarti kingdom, one should offer havans of lotus flowers. For destruction of diseases, one should offer havans of grass, for subduing all creatures, one should offer havans of Patal flowers, for curing fever, one should offer mango leaves, for saving from untimely death, one should offer havans with Mrityunjay mantra, for growth, one should offer havans of sesame seeds. By appeasing Rudra, everyone is appeased.

sarvadahom japyadyai: pathadyaisch ranejaya:.
ashta vimshabhujadhyeya asikhetakavatkarau..
-Aagne. P. Chapter 134

Meaning:- There is always victory in war through havan, chanting and recitation etc. While performing Yagya, one should meditate on Goddess Durga with two arms holding Khang and Khetak in her hands.
shrigehe vishnu gehe va shriyam pujyam dhanam labhet.
aajyaktai standulai lakshi juhuyatkhadiranale..

rajavashyo bhavedva ddhi:shreanchasyadutarottaram.
sarshapaabhyo'bhisheken nashyate sakala graha:..
-aa. pu. au. 307 shlok 3, 4

Meaning:- One should attain wealth by worshiping Goddess Lakshmi through Yagya in the temple of Lakshmi or in the temple of Vishnu. By performing one lakh havan in the fire of Khair with rice mixed with ghee, the king gets controlled and Lakshmi increases gradually.
By anointing with mustard and water, all the planets are destroyed.

shrikam: shantikamo va grah yagnyam samarabhet. 
vrushtayayu: pushtikamo va tathaivabhicharanpun:..
-aa. pu.au. 164 shlo. 1

Meaning:- One who wishes for Lakshmi or wishes for peace, should perform Havan of the planets. One who wishes for rain, age or rainfall should perform Havan of nine planets in the same way.
sansadhyeshanamantren tilhomo vashikar:.

jaya padmastu durvabhi: shantikam: palashajai:.. 
pushti:syatkak pakshen mrutirdvashaadikam bhavet. 
grahakshudrabhayapattim javamev manurbhavet..
-aagne. pu.au. 307 shlok 20, 21

Meaning:- By performing Havan of sesame seeds with the proven Ishaan Mantra, everything becomes under control. Victory is achieved by offering lotus. Those who wish for peace should perform the Havan of Doob. By offering Havan of Palash flowers, it is confirmed. All evil spirits end from Kaak Paksha. It seems as if asteroids, fear, objections all get destroyed.

puspam kshipayayechishya manayedagni kundakam. 
yavaiddhanyastilai: rajyo mulvidya shatam hunet..
sthavaratvam pura homam sarisrupmat: param.
pakshimrug pashutvam ch manusham brahmamev ch.. 
vishnutvanchaiv rudratvamante purnaahutirbhavet.
ekayachaivahyahutya shishyasyaddikshito bhavet.. 
moksham yatiparam sthanam yadgatva na nivarttate.
yatha jale jalam kshiptam jalandehi shivastatha..

Meaning:- Flowers should be thrown, fire should be asked from the disciple, yav, grains, sesame seeds, ghee etc. should be given as hundred offerings with the basic mantra.
First perform havan for immobile beings, then for reptiles, then for birds, deer, animals, for humans and perform havan for Brahma, then for Vishnu, then for Rudra and finally offer Purnahuti.
With a single havan, the disciple is initiated. In this way, he attains that place which is Moksha, where a creature does not return.
Just as water does not separate when poured into it, similarly this body is water and Shiva is also in the form of water. The water in the form of body does not return after mixing with the water in the form of Shiva.
charunas ghrutenaiv kevalam payasapiva.

juhuyat kalamrutyorva pratikar: prakeetrtit:..
-lim. pu.au. 53 shlo. 4

Meaning:- By performing havan with ghee mixed with Charu or only with milk with the Mrityunjay mantra, time and death are countered.

tabaddhomam tilai: kuryadachyutadrdhanpurvakam.
dinanath janebhyastu yajaman: prayatnat:..20..
tavach bhojanam dadyadyavadvobham samacharet.
samaapte dakshinam dadyat rutvibhyashradrdhayanvit: ..21..
yatha ta na labhen tat: shantyudaken ch.
prokshayetmaamamadhye tu vyadhitamntuvisheshat: ..22.. 
evam krute tu homasya purasya nagarasya ch. 
rashtrasya ch mahabhag rajo janapadasya ch ..23.. 
sarvayaasha prashamani shantibhavati sarvada. 
markandeya uvach- ityetacchhaunak proktam kathitam nrupanandan. 
lakshahomadikavidhim rashtra karya sushantidam ..24.. 
prame gruhe va puravahyadeshe dvijairaye yatnakrut: purovidhi:. 
tatrapi shantibhavita naranam gavaam ch bhrutyai: sah bhupatesch ..25..
- nrusingh puran au. 25

Meaning:- Till the target numerical or Koti numerical Havan is not performed, till that time the Lord should be worshiped and Havan should be done with sesame seeds. The host should provide food to the destitute and orphans and give Pushkal Dakshina to the Ritvijas in the Yagyant and should do the prokshan in the middle of the village by reciting peace mantras from Kalshodak and should give special protection to the sick and sad people. By performing Homa in this way, there is welfare of the town, the city, the nation, the state and that country and one attains eternal peace that calms all the obstacles.
In the fire established as per the rules, perform havan with honey soaked havishya, grapes, banana, matuling, sugarcane, coconut, sesame, jatiphal, aak and other sweet substances three times with ten repetitions of each mantra of Saptashati and also perform havan with one thousand Navvarna mantra. Then perform havan for the covering deities with their name mantras and offer Purnahuti in a proper manner. After that immerse the fire along with the Brahmins and deities. Anoint the Yajaman with the water from the Kalash. By doing this, the world comes under your control and all troubles are destroyed.
The above mentioned evidences have been used to describe the yagnas for various siddhis. This is just a glimpse. If we look in the ancient texts of Vedas, we get numerous yagna rules, benefits of yagna, glory of yagna which not only gives the human being extrasensory powers but also gives visible and invisible, physical-spiritual, mundane and transcendental siddhis.

Sahasrambhar: Shuchijihno Agni:. -Rig. 2.9.1

The sacrificial fire with sacred flame provides thousands of benefits.