In a webchat with viewers, Blyth was asked about roles including Jasmine Thomas and Scott and Kelly Windsor.
Ben Freeman (Scott Windsor) was dropped by the ITV soap in 2007 and has since said that he no longer wishes to come back.
On a potential return for Scott and his sister Kelly (Adele Silva), Blyth said that it is "an option".
"A show like Emmerdale creates that type of history to shape the future. So you never know."
Asked if Jenna-Louise Coleman could reprise her part as Jasmine Thomas, who exited the show early last year, Blyth replied: "I love Jenna as an actor so I would be daft to never consider her character returning. But obviously that's Jenna's call, too."
During the webchat, Blyth also defended an on-screen gay kiss between Aaron Livesy and Jackson Walsh.