Its all in wikipedia buddy, I will do a check now for you and post the system with more games, I think its NES, PSX or PS2.
edit: This list does not cover pirated games.
-Atari-
Atari 2600: 565+, 163 by Atari and Sears, 380 by third-parties.
Atari 5200: 69.
Atari 7800: 59 , as well as an estimated 14 aftermarket.
Atari ST: (?) IDK and will not count one by one in that enormous list.
Atari XEGS: 32.
Atari Jaguar: 82, 15 were for Jaguar CD.
Portables
Atari Lynx: 72
-Bandai-
Potables
WonderSwan: 100+ (counted it very fast)
WonderSwan Color: 102.
-Commodore/Amiga-
(?) IDK and will not count one by one in that enormous list.
-Magnavox-
Odyssey: 27 games distributed in 12 different cartridges.
Odyssey2/Videopac: 69 games, plus 3 expansion modules and 24 games made by third-parties.
-MSX-
(?) IDK and will not count one by one in that enormous list.
-Nintendo-
NES: 709 in the US and PAL region.
Famicom: 1,055 plus 229 on Famicom Disk System.
SNES: 784, 250 were exclusive to North America and 63 to Europe.
Super Famicom: 1,442 plus 231 on Satellaview.
Virtual Boy: 22, only 14 made it to North America. (LOL)
Nintendo 64: 387, 84 were exclusive to Japan, 50 to North America, and 4 to Europe.
GameCube: 649.
Wii: 1222 as of May 23, 2013.
Portables
GB: 814.
GBC: 469.
GBA: (?) IDK and will not count one by one in that enormous list.
DS: According to Nintendo of America, there are over 1150 as of February 12, 2011.
-Sega-
Master System: 318.
Mega Drive/Genesis: 918 (plus 220 for Sega/Mega CD and 40 for 32X).
Sega Saturn: 596.
Dreamcast: 720 (including unlicensed games).
Portables
Game Gear: 363.
-NEC-
PC Engine/Supergrafx (Hu Card): As March 2011, this list is complete up through early 1990. And total of 287 games in Japan total. More games were released for the PC Engine beyond that point. Plus 94 games for the TurboGrafx-16 in the U.S.A. and Canada.
PC FX: 62.
PC Engine CD: 417, only 45 were officially localized for the TurboGrafx-CD.
-SNK-
Neo Geo (MVS, AES+CD): (?) IDK and will not count one by one in that enormous list... BUT I remember its more or less 300 because of a emulator that I had.
Portables
Neo-Geo Pocket Color: 85.
-Sony-
Playstation: 2,418.
Playstation 2: 3, 870.
Playstation 3: 772 games as of January 14, 2013.
Portables
PSP: 807 games available and 15 games in the upcoming list as January 13, 2013
-Microsoft-
Xbox: 917 (284 exclusive to North America, 58 exclusive to Europe, 24 exclusive to Japan, and three exclusive to Australasia).
Xbox 360: 959 as of June 6, 2013.
Xbox One: Movies xD