Left-back Anderson(pictured) arrived at the Gallagher Stadium last summer, making more than fifty appearances in his debut season.
Prestedge has just completed his second season with the Stones, having initially joined on loan from Bromley for the second half of the 2016/17 campaign.
He too made more than fifty appearances for the club.
Saunders told the club`s official website: “Even after seven years in the job these are not easy calls to make but it’s part and parcel of football.
“Ando and Prez were big characters in the dressing room and on the pitch and I’d like to thank them both for all they’ve done for the club. They’ve always given me 100% and are a credit to themselves.
“I am aiming to speak to all the players this week and once that’s done I can focus on those targets we’d like to bring in over the summer”.