The lifeblood of Gundam series! Like the asian toys, the kits are numbered:
 Captain Gundam
 Zapper Zaku
 Winged Knight Zero
 Tempest Knight Tallgeese
 Grappler Gouf
 Darkness Knight Deathscythe
 Gundam Force vs. Dark Axis (see below!)
There are some more kits sneaking around in the BB Senshi line:
 Heavy Weapon Captain Gundam
 Zapper Zaku Heavy Armed Type
 Hyper Captain
There are some more kits that are tied to Musha Retsuden, the kind-of related manga:
 Rekka Musha Gundam
 Kidou Musha Rekka Dai-Hagane
 Tekki Musha Psycho
There are others, those are just what I found on HLJ. ^^;
There are some promo kits, too; I only know of a Captain Gundam and a Zapper Zaku. The Captain one came with the April 2004 issue of Comic BOMBOM, a monthly magazine that serialized the SDGF manga.
The Gundam Force vs. Dark Axis set is a sort of model-kit-board-game. It includes a bunch of little kits (including a Special Color version of Heavy Weapon Captain Gundam) and.. other things.. that I don't know because I don't have one. :O There's a little more information at HLJ's page (too bad they don't have it in stock anymore).
Such as, a set of Gundam Markers:
Gundam Markers are painting markers used for detailing kits; they're not great at major painting, but good for detailing and possibly laying base coats for other paints (I'm not certain about that, but I've seen some customizers use them that way).
The SDGF set is six markers: Gold, Silver, Red, Yellow, Grey and Metallic Green.