I should really clarify this on the wiki. We changed how rarities work in 0.7.9. The rarities you see on the Wiki are just spawn rates for the dump. Rarities you see in your chipendium are dynamic, based on how many exist in-game.
The dump spawning will be largely reduced in 0.9.0, completely removed in 1.0.
As @Bkells explained, anything labelled "Unique" is disabled from spawning in the dump. They can either be obtained via trading players, fusion, or chip codes (typically during events).