Riki Lindhome as Ramona Nowitzki
Played by Riki Lindhome, Ramona Nowitzki first appeared in Season 2 as a CalTech graduate student with feelings for Sheldon. Her affection for him soon became stalkerish and got on Sheldon's nerves. The last time Sheldon saw Ramona, her lingering obsessive tendencies drove him to propose to Amy.
Alessandra Torresani as Claire
Alessandra Torresani played Claire, a writer for a children's science fiction series. She met Raj and Howard in the comic book store during Season 9 and soon became involved in a love triangle between Raj and Emily. In the end, Raj attempted to date them both, but the plan blew up in his face.