Shamyapras

Vyasa had his ashram in Shamyapras.

Sveccha Mrityu

Sva (self) Iccha (will) Mrityu (death) – the self-determination of the time of death.

Bhishma had this gift. 

Saila

Achala, Adri, Giri, Parvat, Saila are terms for mountain.

Satyajit

Son of King Drupada.

Shitala

The Goddess of smallpox. Her consort is Jvarasura, the fever.

In south India she is called Mariamman.

Read about Shitala here
https://www.omashram.com/news/the-day-of-shitala-devi

Shatasringa

A mountain in the area of which Pandu stayed with Kunti and Madri after he had left Hastinapura due to the curse of Kindama.Here their sons, the Pandavas, were born. Bhima once fell out of Kunti’s hand and the mountain crumbled.

Shankhachuda

A demon, the reborn Sudama, married with Tulsi, killed by Shiva.

It is a similar story as Vrinda and Jalandhara. In both stories Vishnu is cursed to become a salagrama.

Read about Shankhachuda here
http://hindumythologybynarin.blogspot.com/2013/10/shankachuda-demon-killed-by-shiva-and.html

Surya Kaladi

A master of rites from Kerala.

Read about Surya Kaladi here
http://keralamythology.blogspot.com/2014/01/surya-kalady-kerala-tantric.html

Suparshva

Son of Sampati.

Sphatika Linga

A crystal linga.

When Shankara visited Shiva on Mount Kailash he got five Sphatika Lingas and brought them to five places.

In India: Kanchipuram, Sringeri, Kedarnath, Chidambaram.
In Nepal: Nilakanta Kshetra (which I could not locate under this term).