There are no main characters (or minor characters I can think of) from Star Trek TNG named or referred to as "Six". "Six" however is a human cylon model from the new Battlestar Galactica
Perhaps the OP is referring to the character 'Seven' as in 'Seven of Nine', a former borg drone on Star Trek: Voyager.
Season six, Episode 233, "Rascals"
In the Star Trek: The Next Generation episode Unification I, Spock's father Sarek dies at the age of 203.(Although Mark Lenard appeared as Sarek in only one episode of the original series, he ended up reprising the role of Sarek six more times:as the voice of Sarek in the animated series episode Yesteryear,in the movie Star Trek III: The Search for Spock,in the movie Star Trek IV: The Voyage Home,in the movie Star Trek VI: The Undiscovered Country,in the Star Trek: The Next Generation episode Sarek, andin the ST:TNG episode Unification I.)
Eleven So far: Star Trek: The Motion Picture Star Trek II: The Wrath of Khan Star Trek III: The Search for Spock Star Trek IV: The Voyage Home Star Trek V: The Final Frontier Star Trek VI : The Undiscovered Country Star Trek: Generations Star Trek: First Contact Star Trek: Insurection Star Trek: Nemesis Star Trek
John Copage has: Played 1st U.N.C.L.E. Agent in "The Man from U.N.C.L.E." in 1964. Played Porter in "The Killers" in 1964. Played Phone Repairman in "Bewitched" in 1964. Played Valet in "Mission: Impossible" in 1966. Played Elliott in "Star Trek" in 1966. Played Officer in "Judd for the Defense" in 1967. Played Henry Yardley in "Julia" in 1968. Played Second Policeman in "Julia" in 1968. Played Lumberyard Employee in "With Six You Get Eggroll" in 1968. Played Bill Anderson in "Julia" in 1968. Played Reporter in "Simon, King of the Witches" in 1971. Played Gardener in "Star Trek: The Next Generation" in 1987. Played Command Division Officer in "Star Trek: The Next Generation" in 1987. Played Science Division Officer in "Star Trek: The Next Generation" in 1987.
In season 3, episode 159, "The Hunted" he plays Prime Minister Nayrok and in season six episodes 242 and 243, "Birthright I and II" he plays Jaglom Shrek.
There are 726 episodes of Star Trek in total: 79 episodes of The Original Series + 1 pilot 22 episodes of The Animated Series 178 episodes of The Next Generation 176 episodes of Deep Space Nine 172 episodes of Voyager 98 episodes of Enterprise
Star Trek (aka The Original Series) 1966-1969ST: The Animated Series 1973-1974ST: The Next Generation 1987-1994ST: Deep Space Nine 1993-1999ST: Voyager 1995-2001Enterprise 2001-2005Discovery 2017-Current
"Second Chances," in season six.
The current generation is VI or six with the release of Pokemon X and Y.
Believe it or not Voyager is only seen landing on six different planets.
six generation is a network bandwith
"The Simpsons," television's longest-running primetime scripted comedy series, has won 31 Primetime Emmy Awards. During its two decades on the air, "The Simpsons" has received 15 Emmys for voice-over performances, 10 for Outstanding Animated Program, two for Outstanding Music and Lyrics and four for Outstanding Individual Achievement in Animation.