Rick Grimes was left alone for several weeks while in a coma inside of the hospital. He would find the company of the Jones family until leaving to find his family where he again remained isolated until encountering Glenn. (Issue 1)
Glenn was often isolated during his scavenging trips. (Issue 2)
Michonne spent an undisclosed, yet ample amount of time isolated from humanity before and after collecting her "pet zombies". (Michonne Special)
Following the Prison attack, several survivors became isolated from their respective groups, most notably Michonne, Rick and Carl Grimes. (Comic Series)
Following the death of his son Duane, Morgan Jones had been isolated from humanity for an undisclosed amount of time until he was picked up by Rick. Those he did encounter he would either kill or ignore after seeing how dangerous they were. (Comic Series)
Rick and Carl come across a lone survivor who seemingly walked into a horde of zombies after abandoning his vehicle that was full of gas and supplies. (Issue 51)
In light of the barn massacre and his realization that his family and friends were dead rather than sick, Hershel Greene abandons his farm and the other survivors to go drinking in town. (Nebraska)
Carl Grimes goes into the woods alone and encounters a zombie which he first throws stones at and tries to kill until it gets free and he runs for his life. (Judge, Jury, Executioner)
Dale Horvath goes for a walk in the woods by himself, disgusted by the way his fellow survivors are dealing with Randall and ends up getting ripped open by the walker Carl encountered before. (Judge, Jury, Executioner)
Morgan is discovered by himself, his wife and son now dead. (Clear)
The Prison Survivors that are present during the walker attack in Cell Block D isolated themselves from the remaining Survivors in Cell Block C to contain the unknown sickness that spreads in the Prison. (Infected)
Rick isolates Carol from the Prison group following a supply run, believing everyone (including himself) will distrust her when the truth comes out about Karen and David, and that Tyreese will try to kill her. (Indifference)
Caesar and Shumpert abandon Philip after the Woodbury Massacre, leaving him by himself with little supplies.
The Chalmers family stayed put in their apartment room after the outbreak.
The Prison Bus leaves, with Bob, Maggie, and Sasha having to figure out how to leave.