GTA V : Cameos -IGN

GTA 5 features Cameos by characters from other GTA games.
In the mission Hood Safari the original gangsterx from San Andreas make an appearance. While heading south towards the drug pick up you’ll spot three gang members clad in green head right- instead of left. Follow them and see CJ, Sweet and Ryder from GTA: San Andreas.


Sonny Bottino from GTA IV is referenced again. Even though you never see him, he was Don Jon Gravelli's right hand man. During the random event mission "Burial", You have to save his daughter with any one of the 3 characters up in Blaine County, and drive her back to her dads house in Vinewood. While driving, she will tell you about her Father's life and how "He pretty much ran east coast in the 80's and 90's until he got pinned for murder in Vice City and had to go into hiding in SA." 
Brucie Kibbutz returns on Bleeter, GTA’s equivalent to Twitter. Also during a news announcement on the radio Brucie Kibbitz is mentioned to have gotten into the testosterone replacement market. He sells testosterone from bull sharks.
Niko Bellic is mentioned during the first heist, described as an “Eastern-European” that was making a name for himself back in Liberty City and got out of the business. His LifeInvader profile can be seen on a laptop in Michael's dining room.
Johnny Klebitz from GTA IV. Johnny appears with his girlfriend Ashley in a memorable scene when you first take control of Trevor.


The United Liberty Paper Contact from GTA IV makes a very brief appearance near the end of the mission Monkey Business. Also making another appearance in the mission The Wrap Up, during this mission he can be killed by the player.
Michelle/Karen from GTA IV appears in a cutscene during Three's Company threatening Mr. K with a flashlight


Patrick "Packie" McReary from GTA IV appears in a dynamic event. Franklin can help him during a heist, and he’ll be part of your crew for the rest of the game. Below is a video of how to obtain "Packie."


El Burro Heights is named after one of the characters you perform jobs for in GTA III.
DJ Lazlow, who's previously appeared on the radio in GTA III, GTA:VC, and GTA:SA, makes his first on-screen appearance at the "Fame or Shame" auditions as the host of the show, during the mission of the same name.
Marnie, a drug addict from GTA IV, appears in the Epsilon questline.
Fernando Martinez, a radio personallity who has appeared in GTAIII, GTA:VC, GTA:SA, GTA:VCS, and Episodes of Liberty City makes another return to the radio.
John Marston from Red Dead Redemption makes an appearance as an optional father in the character creation of GTA Online. (When creating ones character online, during the heritage section, the player has the option to select ones parents. When selecting the player's father you can access the option of "Special Father" by hitting 'Y' (Xbox 360) or 'Triangle' (PS3) this will select John Marston as the player's father.) Some gamers have reported that Claude, the protagonist from GTA III, was occasionally available this way before patches were released.
In Trevor's trailor in Sandy Shores, there is a small Western styled hat, possibly an allusion to Red Dead Redemption's John Marston; it should be noted, however, that this hat is camoflauge colored, which John's was not.
In Lester's house, there is a book in one of the shelfs that has a picture of CJ in the cover.