Here is the list of reveal dates.
Super Smash Bros. Melee
Fox - July 7, 2001
Samus - July 10, 2001
Ness - July 17, 2001
Bowser - July 24, 2001
Mario - Aug 7, 2001
Captain Falcon - Aug 14, 2001
Kirby - Aug 21, 2001
Donkey Kong - Sept 4, 2001
Link - Sept 18, 2001
Pikachu - Sept 25, 2001
Peach - Oct 2, 2001
Ice Climbers - Oct 9, 2001
Yoshi - Oct 23, 2001
Sheik - Oct 30, 2001
Zelda - Nov 16, 2001
Luigi - Nov 27, 2001
Marth - Dec 4, 2001
Pichu - Dec 11, 2001
Ganondorf - Dec 18, 2001
Jigglypuff - Dec 25, 2001
Dr. Mario - Jan 1, 2002
Falco - Jan 1, 2002
Mewtwo - Jan 8, 2002
Roy - Jan 15, 2002
Young Link - Jan 22, 2002
Mr. Game and Watch - Jan 29, 2002
Super Smash Bros. Brawl
Link - May 23, 2007
Mario - May 23, 2007
Pit - May 25, 2007
Pikachu - June 7, 2007
Kirby - June 7, 2007
Fox - June 11, 2007
Samus - June 15, 2007
Wario - June 20, 2007
Zelda - June 25, 2007
Bowser - July 3, 2007
Donkey Kong - July 10, 2007
Zero Suit Samus - July 19, 2007
Yoshi - July 24, 2007
Ike - Aug 1, 2007
Pokemon Trainer - Aug 13, 2007
Peach - Aug 17, 2007
Diddy Kong - Aug 22, 2007
Metaknight - Sept 5, 2007
Ice Climbers - Sept 14, 2007
Snake - Sept 21, 2007
Lucas - Oct 1, 2007
Sonic - Oct 10, 2007
King Dedede - Oct 25, 2007
Pikmin & Olimar - Jan 9, 2008
Sheik - Jan 16, 2008
Ness - Feb 1, 2008
Marth - Feb 7, 2008
Luigi - Feb 15, 2008
Falco - Feb 20, 2008
Captain Falcon - Feb 22, 2008
Lucario - Feb 28, 2008
R.O.B. - March 6, 2008
Mr. Game and Watch - March 10, 2008
Ganondorf - March 18, 2008
Jigglypuff - March 25, 2008
Toon Link - March 28, 2008
Wolf - March 31, 2008
Super Smash Bros. Wii U and 3DS
Mario - June 11, 2013
Link - June 11, 2013
Pit - June 11, 2013
Kirby - June 11, 2013
Pikachu - June 11, 2013
Fox - June 11, 2013
Bowser - June 11, 2013
Donkey Kong - June 11, 2013
Samus - June 11, 2013
Mega Man - June 11, 2013
Villager - June 11, 2013
Wii Fit Trainer - June 11, 2013
Pikmin & Olimar - July 12, 2013
Luigi - Aug 7, 2013
Peach - Sept 12, 2013
Toon Link - Sept 26, 2013
Sonic - Oct 1, 2013
Marth - Nov 7, 2013
Rosalina & Luma - Dec 18, 2013
Zelda - Dec 26, 2013
King Dedede - Jan 10, 2014
Lucario - Jan 31, 2014
Little Mac - Feb 13, 2014
Diddy Kong - Feb 21, 2014
Zero Suit Samus - April 8, 2014
Sheik - April 8, 2014
Yoshi - April 8, 2014
Charizard - April 8, 2014
Greninja - April 8, 2014
Ike - May 23, 2014