Star Trek: Picard: Easter Eggs and References in Episode 5, "Stardust City Rag"

Icheb

This episode briefly brings back another Star Trek: Voyager character. Icheb appears in Seven of Nine's flashback that opens the series.

Icheb was one of a group of children who were assimilated by the Borg. Voyager discovered them and took them on board the ship. Seven became like a mentor to them, and a mother figure to Icheb.

Orion Girl

One of the holographic signs over Freecloud is a dancing Orion girl. This is a reference going all the way back to Star Trek: The Original Series.

Orion "animal women" are highly prized "commodities" that the Orion Syndicate traffick on slave markets. Supposedly, no human can resist their dancing. They appeared in the original pilot for Star Trek, "The Cage," and later in episodes of The Original Series and Enterprise.

The Delta Quadrant

The Delta Quadrant is a region of space that borders the Gamma and Beta Quadrants. As Earth is located in the Alpha Quadrant, the Delta Quadrant is about as far away from humanity's home as you could get within the galaxy.

In the year 2371, an alien being flung the Starfleet vessel USS Voyager into the Delta Quadrant. Star Trek: Voyager chronicled the ship's long journey home.

Bolian

When the La Sirena arrives at Freecloud, Rios gets a holographic advertisement for The Red Bolian. Bolians are an alien species in the Star Trek universe, though they are blue-skinned.

Bolians come from the planet Bolarus IX. As of the Star Trek: The Next Generation era, several Bolians served in Starfleet.

Mr. Mot

Speaking of Bolians, Freecloud has a sign for Mr. Mot's Hair Emporium. This seems to be a reference to a character from Star Trek: The Next Generation.

Mot was the Bolian barber aboard the Enterprise. It seems he's struck out into new ventures since then.

Quark's Bar

In Star Trek: Deep Space Nine, the local watering hole aboard the space station was Quark's Bar. The bar seems to have expanded its presence in the years since then.

As Rios beams down to Freecloud, we see that a Quark's Bar location has opened here as well. It seems business is good for Quark. Speaking of which...

Quark

Quark himself gets a mention during the job on Freecloud. Raffi put together a "facer" persona for Rios before beaming him down to Freecloud. Part of that persona included a high recommendation from "Quark of Ferenginar."

Ferenginar is the Ferengi homeworld. Its unclear if this means Quark finally left Deep Space 9 behind, though that would make sense if he's now running a whole chain of Quark's Bar locations.

Breen

It is said that Quark had a problem with the Breen. The Breen are an isolated, warrior-like species from the planet Breen.

The Breen are secretive and little is known about how the Breen Confederacy functions. No has seen what the Breen look like under their helmets.

The Breen allied themselves with the Dominion during the Dominion War, as chronicled in Star Trek: Deep Space Nine. One of their first acts was to attack Earth and destroy Starfleet headquarters.

The Neutral Zone

Seven is now a member of the Fenris Rangers. During her conversation with Picard, she mentions that the Rangers patrol the region that used to be called the Neutral Zone.

The Romulan Neutral Zone was an area of space between Federation space and space belonging to the Romulan Star Empire. No ship from either faction was allowed to enter that space without good reason. This was a source of tension in several episodes of Star Trek.

The Neutral Zone was established by a treaty that ended a war between Earth and the Romulan Empire. The war also was a motivation for the creation of the United Federation of Planets. It seems that the destruction of Romulus and the Romulan diaspora meant there was no longer reason and/or means to keep the Neutral Zone as it was, and it has instead become a kind of no man's land.

Annika

At one point, Seven of Nine is referred to as Annika. This was her original human name. She was born Annika Hansen.

Based on the conversation, it seems that Seven may have reverted to using her original human name for a time after arriving on Earth with Voyager. Bajazel's betrayal and the death of Icheb then seemingly drove her back to using her Borg name, Seven.

Voyager

Seven mention Voyager. This is the USS Voyager, the titular starship vessel featured in Star Trek: Voyager.

Seven joined the Voyager crew in the show's fourth season. She was sent to the ship to speak on behalf of the Borg Collective, but the Voyager crew severed her ties to the hivemind.

Voyager theme

As Seven beams back down to Freecloud to settle her score with Bajazel, a familiar French horn plays. This is the opening to the Star Trek: Voyager theme song.

Star Trek: Voyager followed the titular vessel after it was flung into the far reaches of the Data quadrant. It had an unusual crew, made up partly of enlisted Starfleet officers, partly of members of the rebel Maquis faction, and partly of Delta Quadrant natives like Seven.

Dr. Soong

Bruce Maddox mentions the work of Dr. Noonian Soong. Soong created Data and his brothers, Lore and B-4.

Maddox studied Soong's work and continued it after his death. The fruits of that labor are Dahj and Soji, Data's daugthers.