Gretchen Trimbol was a recurring character in FtWD, she is portrayed by Rae Gray.
Gretchen is part of the prepper community led by Jeremiah Otto just north of the US/Mexico border.
Gretchen forms the start of a good relationship with Alicia but then leaves the ranch with her family at the start of the episode "Red Dirt". The family were immediately tracked down and killed by Troy Otto. When Gretchen was found by Madison, Jeremiah Otto and Nick, she was zombified and eating one of the family's two horses. Nick put her down, Madison and Jeremiah could not bring themselves to do it.