These are the ships from various other quantum realities from Lower Decks season 5. They need to be taken with a lot more than the usual grain of salt. Even though it may be plausible for some of the designs to exist somewhere, there is no reason why a Sovereign-class Cerritos should be the "twin" of our Cerritos (just because of the name?). And this is still one of the less crazy examples.
Starfleet Ships
Beagle type
General description
The Beagle is a ship from a parallel universe where Cochrane and Sloane didn't invent warp propulsion but the quantum reality drive. The design includes an annular drive section that can be folded in order to land on planets. Time frame: 21st century.
Known ships
USS Beagle
Annotations
The USS Anaximander encounters Lily Sloan and the USS Beagle in LOW: "Fissure Quest". The ship is destroyed when Lt. Kim hijacks it and enters an interdimensional fissure, although the repairs are incomplete.
The design resembles the obscure USS Enterprise XCV 330 from our universe. The proportions of the hoops are different, however, and there is an additional mid-section with some sort of tanks and panels.
It doesn't seem realistic that a prototype ship from 21st century Earth would feature a complex mechanism to be able to land on planets. But the design may have been upgraded in realities/times where humanity is more advanced. I take it for granted that interdimensional travel in LOW season 5 sometimes involves time travel, and the Beagle is the most definite case.
It is the USS Beagle, although there likely isn't a Federation in Sloane's time and/or universe.
This parallel version of the California class has only a single nacelle.
Known ships
USS Cerritos NCC-75567
Annotations
The USS Cerritos gets temporarily transformed into this ship while in the Schrödinger field in LOW: "The New Next Generation".
Boimler says: "We're in the Cerritos from a reality where it's a Freedom-class." But not every single-nacelled ship has to be a Freedom class. Boimler may have just picked the Freedom for comparison because a California class with one nacelle isn't a thing in our universe. There is nothing like a display reading "Freedom class".
Class specifications
None available
California (single nacelle & yellow)
General description
This parallel version of the California class has only a single nacelle and large parts of the hull (and of the interior) are yellow.
Known ships
USS Cerritos NCC-75567
Annotations
A little later in LOW: "The New Next Generation", the Cerritos gets transformed into a ship of the same one-nacelled type as above, but with many parts of the hull (and of the interior) being yellow. It is listed separately as all ships from different quantum realities, as much as they may resemble each other.
Class specifications
None available
California (Terran)
General description
This is the Mirror Universe equivalent of a California class, with a formidable armament and nacelles similar to those of the Sovereign class.
Known ships
ISS Cerritos
Annotations
The USS Cerritos gets temporarily transformed into this ship while in the Schrödinger field in LOW: "The New Next Generation".
This is an escape pod found in another quantum reality.
Known shuttles
No name given
Annotations
Lieutenant Kim is rescued from such an escape pod in a debris field in LOW: "Fissure Quest". In our universe, it is the type used on the Defiant and on the Intrepid class. So it makes sense if Lt. Kim served on a USS Voyager.
This may be a Miranda class from a parallel universe, with nacelles that resemble the ones of the California class.
Known ships
USS Cerritos NCC-75567
Annotations
The USS Cerritos gets briefly transformed into this ship while in the Schrödinger field in LOW: "The New Next Generation".
If we go by the MSD and by the type of the nacelles (without the assumption they are scaled down), then this ship is eight times the size of a Miranda class. In other words, it isn't a Miranda. I list the ship as a Miranda for the sake of simplicity, not because I would endorse the idea that the same basic classes come in different sizes.
This is an Oberth class from a parallel universe, which appears to be identical to the one of our universe.
Known ships
USS Cerritos NCC-75567
Annotations
The USS Cerritos gets briefly transformed into this ship while in the Schrödinger field in LOW: "The New Next Generation".
Considering how much smaller an Oberth is compared to the other parallel universe versions, realistically many of the crew should die when the Cerritos changes to this ship (just like the Klingons on the "Barge of the Dead" in the same episode).
This is an Olympic class from a parallel universe, which appears to be identical to the one of our universe.
Known ships
USS Quito
Annotations
The model of the Olympic class can be seen in Becky Freeman's ready room in LOW: "Dos Cerritos". It is definitely meant to be the USS Quito (on which Mariner served), since this universe is very close to ours.
This is a Type-7 shuttle from a parallel universe.
Known shuttles
Joshua Tree (USS Cerritos)
Annotations
Mariner is rescued from such a shuttle in LOW: "Fissure Quest"
This is the first appearance of a "real" Type-7 shuttle with the long window band as originally envisioned by Andrew Probert, which was so far only seen on displays.
This is a Klingon sailing barge from a parallel universe, which only ends up in space by accident.
Known sailing ships
No name given
Annotations
A ship of Relga's fleet gets transformed into a sailing barge in the Schrödinger field later in LOW: "The New Next Generation". The crew gets killed for obvious reasons.
The sailing ship is included in the Starship Database for the sake of completeness. Its design is very similar to the "Barge of the Dead" from the Voyager episode of the same name.
This is a very unusual design from a parallel universe.
Known ships
No name given
Annotations
A ship of Relga's fleet gets transformed into this odd vessel, which has little in common with known Klingon ships, in the Schrödinger field at the beginning of LOW: "The New Next Generation". The crew too mutates to something else than familiar Klingons.
The look of the ship and that of the mutated Klingon aboard is the one established in Discovery season 1, the design of the ship being identified as a "Bird-of-Prey" there. The "new" Klingon look was amended and the "new" Klingon ships largely retired as soon as in season 2 of Discovery, ostensibly because the producers wanted to further develop the series, but more likely because the season 1 designs were anti-canon and extremely unpopular. Although they had been abandoned, the purported official status of Discovery Klingons and their ships so far was "canon in the Prime Universe". The transformation of a BoP into a DIS-BoP in the Schrödinger field, which is explicitly said to transform matter into "multiverse possibilities", allows the interpretation that Discovery is a parallel universe (although other ties between DIS, SNW and classic Trek are still strong). Mike McMahan on the topic: "You can take that moment however you want, and talk to me about it in ten years."