I would say these are mandatory:
Gundam, Mobile Suit 0079 Complete Collection 1
Gundam, Mobile Suit 0079 Complete Collection 2
Gundam, Mobile Suit Movie Trilogy
Gundam, Mobile Suit Zeta Collection 1
Gundam, Mobile Suit Zeta Collection 2
Gundam Mobile Suit 0080 Complete Collection
Gundam 0083...