From Halopedia, the Halo wiki
Post-Great Purification and legacy
After 97,445 BCE, Keyships played a role in the Reintroduction of species to their homeworld. One Keyship, the Anodyne Spirit, was hijacked by Mendicant Bias and would end up crash landing on the San'Shyuum homeworld of Janjur Qom. This ship would be later seen as a religious artifact to the species and would later become part of the Covenant's holy city of High Charity.
A special type of design seed is used to construct Forerunner ships, known as ship-seeds.
List of Forerunner starships
The following is a list of the starships that belong to and are used by the Forerunners.