The colony of advanced androids created by Bruce Maddox and Altan Soong on the planet Coppelius, hunted by the Romulan Zhat Vash and tempted to summon a destructive alliance of synthetic life.
The synths of Coppelius appear in the two-part finale of the first season of Star Trek: Picard, Et in Arcadia Ego. After the ban on synthetic life, Bruce Maddox retreated to the planet with Altan Inigo Soong, son of Data's creator, and built a community of androids, many in matched pairs, from neurons derived from Data. Dahj and Soji Asha were two of them.
When Picard brings Soji home in 2399, a Romulan fleet is close behind. Her sister Sutra, having learned the Admonition through a mind meld, argues for building a beacon to call an ancient federation of synthetics that will wipe out organic life, and arranges the death of one of her own kind to sway the others.
Soong exposes and deactivates Sutra, and Picard's willingness to die for the colony persuades Soji to shut the beacon down. Starfleet under Riker then places Coppelius under Federation protection.