Characters Left

Looking at the character list in the sidebar, seems that since the end of the first season we've lost over half of the characters. I know a lot of them came in during the second season and the third but its beginning to look a bit grey over there.
There likely could be some that are still lit up. The guys from the Atlanta nursing home, the ones that went a different way from the case at the end of the Atlanta camping area....

There were more or less "main" type cast members.
The people from the nursing home didn't make it. It was one of the deleted scenes on the second season blu-ray. The group was over run by other survivors as I forget who mentioned it during the scene. Eventually the walkers roamed in and fed on the bodies. I don't think we're going to learn what happened to the latino family that went on their own way at the end of season one.