The leaves of Bilwa (Aegle marmelos), which has multiple leaves, with each leaf consisting of three leaves is very dear to Lord Shiva. Offering this leaf to Lord Shiva pleases him especially on the Shivarathri .There are several stories how people got salvation by offering one Bilwa leaf to Lord Shiva.
Tridalam trigunakaaram trinethram cha triyayusham,
Trijanma papa samharam Eka bilwam shivarpanam. 1
I offer one leaf of Bilwa to Lord Shiva,
Which has three leaves,
Which causes three qualities,
Which are like the three eyes of Shiva,
Which is like the triad of weapons,
And which destroys sins of three births.
Trishakhai bilwapathraischa hyachidrai komalai
shubai,
Shiva poojam karishyami, Eka bilwam shivarpanam. 2
I offer one leaf of Bilwa to Lord Shiva,
Which has three shoots,
Which do not have holes,
Which are good and pretty,
And worship Lord Shiva.
Aganda bilwa pathrena poojithe nandikeshware,
Shudhyanthi sarva papebhyo, Eka bilwam shivarpanam. 3
I offer one leaf of Bilwa to Lord Shiva,
For if an uncut leaf is offered,
To his steed the god Nandi,
We get cleaned of all our sins.
Salagrama shilamekaam vipranam jatha cha arpayeth,
Soma yagna maha punyam, Eka bilwam shivarpanam. 4
I offer one leaf of Bilwa to Lord Shiva,
For it is equal to, offering a saligrama to a Brahmin,
Or the great blessing got out of performing Soma Yaga,
Dandi koti sahasrani vajapeya sathani cha,
Koti kanya maha danam, Eka bilwam shivarpanam. 5
I offer one leaf of Bilwa to Lord Shiva,
For it is equal to gifting thousand elephants,
Or the performing of hundred fire sacrifices,
Or giving away billions of girls.
Lakshmyasthanutha uthpannam mahadevasya cha priyam,
Bilwa vruksham prayachami, Eka bilwam shivarpanam. 6
I offer one leaf of Bilwa to Lord Shiva,
For it is equal to giving a tree of Bilwa,
Which was born from the breast of Lakshmi,
And which is very dear to the Lord Shiva.
Darshanam bilwa vrukshasya, sparsanam papa nasanam,
Aghora papa samharam, Eka bilwam shivarpanam. 7
I offer one leaf of Bilwa to Lord Shiva,
As seeing and touching of a tree of Bilwa,
Washes away ones sins and also very great sins.
Kasi kshethra nivasam cha kala bhairava darshanam,
Prayaga madhavam drushtwa, Eka bilwam shivarpanam. 8
I offer one leaf of Bilwa to Lord Shiva,
After living in the city of Kasi,
Seeing the Kala Bhairawa,
And also visiting the temple
Of Madhawa in Allahabad.
Moolatho brahma roopaya, madhyatho Vishnu roopini
Agratha shiva roopaya, Eka bilwam shivarpanam 9
I offer one leaf of Bilwa to Lord Shiva,
As Brahma resides at its bottom,
Lord Vishnu lives in its middle,
And Lord Shiva lives in its tip.
Bilwashtakam idham punyaam, padeth shiva sannidhou,
Sarva papa nirmuktha Shiva loka maapnuyath. 10
Reading this holy octet of Bilwa,
In the presence of Lord Shiva,
Would save one from all sins,
And in the end take him to the world of Shiva.
You may check these links also
108 Names and Salutations to Lord Shiva
Shiva Aparadha Kshamapana Stotram, A Prayer Seeking Forgiveness
Bilwashtakam - A Prayer To Lord Siva With Bilwa Leaves
A Prayer To Siva - Chandrasekharashtakam
A Prayer To Lord Chidambara - Chidambareswara Stotram
Daridraya Dahana Shiva Stotram - A Prayer to Shiva To End Poverty
A Prayer to Worship Kalabhairava
Lalitha Sahasranamam: The Thousand Names of Sri Lalitha
Lingashtakam - A Prayer To Sivalingam
Shiva Nama Malyashtakam - A Prayer Extolling The Virtues Of Lord Siva
Shiva Mangalashtakam A Prayer Of Auspiciousness
Margabandhu Stotram - A Prayer To Lord Siva To Show The Right Path
Maha Mrityunjaya Stotram - A Prayer To Lord Siva For Victory Over Death
Nathopadesa Stotram - A Prayer That Teaches The Devotees
Shiva Panchakshara Stotram - A Prayer On The Five Names Of Shiva
Parameshwara Stotram - A Prayer The Supreme Lord Of Universe
Pradosha Mahatmyam - From Shiva Puranam
Shiva Raksha Stotram - A Prayer Seeking Siva's Protection
Sadasivashtakam - Prayer To Siva As Sundareswar
Shiva Sahasra Namam - Thousand Names of Lord Shiva from Mahabharata
Samkarashtakam - A Prayer To Lord Samkara
Sasakti Shiva Navakam Nine Stanzas Extolling The Power Of Shiva
Shiva Mahimah Stotram, A Prayer On The Miraculous Powers Of Shiva
Shivashtakam, A Prayer To Lord Siva
Shiv Chalisa - Forty Stanzas On Shiva in Hindi
Veda Sara Shiva Sthavam, Prayer To The Lord Of The Vedas
Sri Viswanatha Suprabathashtakam
Shiva Thandava Stotram - A Prayer Offered While Doing Tandava Dance
Thiruvempavai, A Penance Observed By Unmarried Girls
The Thousand Names of Lord Siva
Vaidyanatha Ashtakam, A Prayer Addressed To The Lord Of Physicians
Vaidyanatha Namaskaram, Salutations To The Lord Of Physicians