The disks were found in the suva shrine in the Great Temple. Each Kanoka disk was a different color, and each bore the likeness of a Mask of Power. What drew the attention of the Toa Metru was that the masks matched the ones they wore, suggesting that they had always been destined to be Toa.1
Notes
Toa Disks could be used multiple times.2
Each of the Toa Metru weren't in possession of their respective Toa disk.3
The red Kanoka disk that came with Vakama was a Toa disk. Six of them were found in the suva where the Toa found their tools. The presence of Vakama's mask was a hint that these six Matoran were pre-destined to become Toa.4
If Vakama's Toa disk were made into a mask, it would be a Mask of Fire, which would be redundant with Vakama's elemental power of fire.5
The other Toa Metru put their Toa disks somewhere safe, since Vakama was the only one with a disk launcher.6
The individual Toa disks did not have names.7
Use in Mask Making
A Toa disk of Fire could be forged into a Mask of Fire.8 Toa disks could be used to form other masks as well.9
Masks forged from Toa disks would give the wearer power over the element as though they were a Toa of that element.10
Masks forged from Toa disks wouldn't provide the wearer with protection from that element. For instance, a Mask of Fire wouldn't protect the user from burns.11
A Mask of Gravity was likely made from a disk of gravity. That didn't necessarily mean the disk would have to be from a specific Toa; it could've simply been an elemental powered disk.12