Multiple realities(covers information from several alternate timelines)
The following is a list of unnamed Kelpiens.
These villagers lived in Saru's home village on Kaminar. Saru and his sister Siranna witnessed eight of them being harvested by the Ba'ul, in a ceremony presided over by Aradar. Later, Aradar played dice with three other villagers. (ST: "The Brightest Star")
A number of villagers were also seen when Saru returned to his home village, accompanied by Michael Burnham. (DIS: "The Sound of Thunder")
The mother of Saru and Siranna was taken by the Ba'ul, a fact Siranna lamented along with the loss of her father after learning the truth about the Great Balance. (DIS: "The Sound of Thunder")
In the episode, Siranna informs Saru of the taking of their father, but not their mother. This suggests that their mother was taken before Saru left Kaminar.
Mirror universe slaves
Emperor Philippa Georgiou presented Michael Burnham with three slaves to choose from. Unknown to Burnham, the chosen Kelpien was then killed, cooked, and served to her and the emperor. (DIS: "Vaulting Ambition", "The War Without, The War Within")
The chosen Kelpien was portrayed by Clayton Scott. The other two were portrayed by unknown background actors.