"Om Hlim Sham Shanaye Namah"
"Om praam preem praum sah shanayishraya namah"
"Om sham shanayscharaya namaha"
"Aum Aing Hring Shring Shung Shanaishcharaye Namah Aum"
Shani Gayatri Mantra
"Om Sanaischaraya vidhmahe
tanno manda prachodayat"
Shani Dhyan Mantra
Nilanjana samabhasam raviputram yamagrajam
chaya martanda sambhutam tam namami shaishcharam
I bow to Lord Shani, who is black in colour and son of Sun and born to Chaya and brother of Yama , who moves very slowly.
Om Shanno Devirabhishtaya Aapo Bhavantu Peetaye Shanyorbhisravantumah Shanaishcharaaya Namah
Read more on Shani and remedies for shani affliction