OVA

Original Video Animation (オリジナル・ビデオ・アニメーション, Orijinaru bideo animēshon?), abbreviated OVA (オーブイエー / オーヴィーエー / オヴァ, ōbuiē, ōvīē or ova?) (and sometimes as OAV by English-speakers) are considered side-stories, prequels, or sequels of a currently running anime series. In the Gundam universe there are many OVA's and many of them are no more than around 12 episodes long. Stories such as 0083 and Unicorn, tell of the establishment of the worlds and factions found in Zeta Gundam and F91.

Universal Century OVAs
Mobile Suit Gundam 0080: War in the Pocket

Mobile Suit Gundam 0083: Stardust Memory

Mobile Suit Gundam: The 08th MS Team

Mobile Suit Gundam MS IGLOO: Apocalypse 0079

Mobile Suit Gundam Unicorn

After Colony OVA
New Mobile Report Gundam Wing: Endless Waltz - Originally released as a three part OVA and was transformed into a movie.