I'm not sure how many Gundam shows are there but here are the one's I've heard/read/know....
First Gundam (original 1979 TV series)
Gundam I,II,III (compilation movie of the above mentioned TV series)
08th MS Team (takes place during the above series)
08th MS Team Miller's Report (compilation short movie of above OVA)
0080 War in The Pocket (takes place during the above series)
0083 Stardust Memories OVA
0083 Zeon no Zankou (compilation movie of the above mentioned OVA)
Z Gundam
Gundam ZZ
Char's Counter Attack
Gundam F91
V Gundam
Gundam Wing
Gundam Wing ENDLESS WALTZ OVA
Gundam Wing ENDLESS WALTZ movie (compilation movie of above mentioned OVA)
G Gundam
Gundam X
Turn A Gundam
Turn A Gundam I, II (compilation movie of the above mentioned TV series)
GundamSEED
GundamSEED Destiny (airing this fall)
MOBILE SUIT SD GUNDAM (OVA Compilation)
Mobile Suit SD Gundam Part 1: Fierce Fighting - Will Gundam Stand Up? (1988)
Mobile Suit SD Gundam Part 2: Day Off - Menace of the Zeon Hotel? Destruction Orders for the Gundam Pension!! (1988)
Mobile Suit SD Gundam Part 3: Final Arena - SD Olympics! The Stadium Saturated with Laughs (1988)
MOBILE SUIT SD GUNDAM MK-II (OVA Compilation)
The Rolling Colony Affair (1989)
Founder Gundam: The Lost Story (1989)
Gundam Legend (1989)
MOBILE SUIT SD GUNDAM: SD GUNDAM'S COUNTERATTACK (Theatrical Movie)
SD Sengokuden: The Chapter of the Violent Final Sky Castle (1989)
Mobile Suit SD Gundam: The Storm-Calling School Festival (1989)
SPECIAL: MOBILE SUIT SD GUNDAM: SD GUNDAM ENCYCLOPEDIA (OVA?)
SD Gundam Encyclopedia (1989)
MOBILE SUIT SD GUNDAM MK-III (OVA Compilation)
Space's Secret War (1990)
SD Sengokuden: Zumupoopei's Ninja Combination Battle (1990)
SD Sengokuden: The Sky Chapter (1990)
SD Sengokuden: The Earth Chapter (1990)
SD Sengokuden: The Truth Chapter (1990)
SD Sengokuden: The Reason Chapter (1990)
SD GUNDAM GAIDEN (OVA Compilation)
SD Gundam Gaiden: Lacroa's Hero (1990)
SD Gundam Gaiden 2: The Legendary Giant (1990)
SD Gundam Gaiden 3: The Algas Knights (1990)
SD Gundam Gaiden 4: The Light Warrior (1991)
MOBILE SUIT SD GUNDAM MK-IV (OVA Compilation)
SD Gundam Crazy Race (1990)
The Dream Chestnut Company: Journey Through Space (1990)
MOBILE SUIT SD GUNDAM MK-V (OVA Compilation)
Carrier Re-GZ's Miracle (1990)
SD Sengokudan: The Gundam Five's Extermination (1990)
SD Gundam Genesis: Pikirienta Porus (1990)
SD GUNDAM: LARGE MOBILE SUITS PICTORIAL GUIDE (OVA?)
SD Gundam: Large Mobile Suits Pictorial Guide (1990)
SD GUNDAM MUSHA, KNIGHT, COMMAND & DAWN OF PAPARU (OVA Compilation)
Musha, Knight, Command: SD Gundam Emergency Sortie (1991)
Dawn of Paparu, Episode 103: Suginamu's Bride (1991)
SD GUNDAM FESTIVAL (Theatrical Movie)
SD Command Senki II: Gundam Force, Super G-Arms, Final Formula VS Noum Gyaza (1993)
SD Sengokuden: World Peace Chapter (1993)
SD Gundam Gaiden: The Legend of the Holy Machine Soldiers (1993)
SD GUNDAM MUSHA PACK (OVAs?)
SD Gundam Musha Pack: SD Gundam Musha Reiden Present Video (2002)
SD Gundam Musha Pack 2: Birth of New Warrior (2003)
SD GUNDAM FORCE (TV Series)
SD Gundam Force (2004, 26 episodes)
SD Gundam Force Season 2 (2004, 26 episodes)
;D Not sure if that's all the gundam's aout there. ;D