Kirby is not the only one of his kind in his universe. Many Kirbys have appeared throughout the series, and outside of the series too. The following will list other examples of Kirby's species (referred to as 'Kirbys' for the sake of simplicity), both confirmed and suspected:
Kirby is the most notable and famous of his species. He is usually also seen as its representative. However, his ability to inhale and copy has not yet been confirmed to be a species trait or simply something unique to Kirby.
A somewhat obvious example, shown in Kirby & The Amazing Mirror and in Kirby Mass Attack, makes use of Kirby being split into several versions of himself. In Amazing Mirror, these clones shared Kirby's ability to inhale and copy, and at the end went off to become heroes in their own right. In Kirby Mass Attack, the clones are much smaller versions of Kirby, and cannot inhale. Also, the ending of that game has the clones merge back into Kirby.
In Kirby Battle Royale, King Dedede is in possession of a Kirby Printer which is capable of mass-producing Kirby clones (which come in every color except for pink). These clones come with a Copy Ability, and in all likeliness, cannot discard them. When the Kirby Printer is eventually destroyed, all the clones it created vanish.
The player 2 character in Kirby's Dream Course is a yellow version of Kirby officially known as Keeby. In the game, he serves as player 2, competing against Kirby. Like Kirby, he is able to copy abilities from enemies, though it is unknown whether he can float or inhale. As he has never been seen or mentioned again in the series, it is likely that this Kirby is not canon.
Mirror-world Kirby, (otherwise known as Shadow Kirby), is a grey/black version of Kirby that appears in Kirby & The Amazing Mirror. He appears to share the ability to copy and float.
In many Kirby games like Kirby Air Ride, Kirby: Nightmare in Dream Land, Kirby's Return to Dream Land, Kirby Fighters Deluxe, Team Kirby Clash Deluxe and Kirby Star Allies players 2-4 can play as alternately colored Kirbys. These Kirbys, however, are not officially canon.
At the end of Kirby's Dream Land, Kirby can be seen returning stolen food to a crowd of other round creatures that look a lot like him. In Spring Breeze, however, this crowd was ret-conned into one made mainly of Waddle Dees.
It is popularly speculated and widely believed that Meta Knight and Kirby are the same species. Evidence pointing in favor of this conclusion includes their similar shape, body structure, and face (when unmasked). Additionally, the anime explains that both Kirby and Meta Knight are part of an order of Star Warriors who tend to share a similar origin (though even if taken into consideration, this reasoning is imprecise, as Star Warriors themselves also tend to come in different types).
However, a number of key differences exist between Kirby and Meta Knight, many of which were established in later titles. Meta Knight is often depicted with wings, which is a feature that Kirby cannot obtain without the use of the Wing ability. However, in the Super Smash Bros. games, these wings are shown to be a transformation of his cape, which eventually was demonstrated in the Kirby series proper in the opening cut-scene of Kirby: Planet Robobot. Meta Knight also has glowing yellow (but otherwise featureless) eyes, which is another trait that Kirby lacks. As a final note, Meta Knight has never been shown to be able to inhale, which is something that Kirby and all of his clones are capable of doing.
Ultimately, there is no conclusive proof in either direction, but the fan consensus still tends to tip toward Meta Knight and Kirby being the same species. This is augmented by the way Meta Knight is often compared to Kirby in the games and in descriptions, with examples including the eighth palette swap of Kirby in Super Smash Bros. 4 and onward, and in his description in Palutena's Guidance, also in Smash 4 and onward.
Dark Meta Knight
Only seen for a brief moment after he is defeated at Radish Ruins in Kirby & The Amazing Mirror, Dark Meta Knight's unmasked form resembles a black Kirby, darker than even Shadow Kirby. However, it is unknown whether he is an actual evil Kirby working for Dark Mind or merely a replica of Meta Knight created by Dark Mind.
At the end of the Meta Knightmare Ultra subgame of Kirby Super Star Ultra, Meta Knight battles Galacta Knight, the greatest warrior in the galaxy. Galacta Knight in many ways resembles Meta Knight and therefore Kirby in shape and size. However, Galacta Knight's maskless form is never seen, even when he is defeated. In addition, his wings appear to be a natural fixture, rather than the cloak that comprises Meta Knight's. The same can be said for Morpho Knight, an entity derived from Galacta Knight that bears a similar appearance (but notably lacks a mouth).
In Kirby's Epic Yarn and Kirby's Extra Epic Yarn, Kirby's primary helper is Prince Fluff, a resident of the world transformed into Yarn. Prince Fluff, like Kirby in his yarn state, is unable to inhale or float, though he is capable of transforming himself into other shapes like Kirby can. It is unclear if Fluff is the same species as Kirby, or if they just happened to look similar when Kirby was transformed into a yarn outline like him.
In Kirby's Dream Land 3, mysterious enemies known as "Batamon" are often seen in locations impossible for Kirby to access. These enemies look very similar to Kirby, but bear a slightly different body shape and face structure.
- Main article: Anti-Kirby
In The Legend of Zelda: Link's Awakening, there are enemies called Anti-Kirbys who can attack Link by inhaling him, and then spitting him out. These Kirby-like foes are immune to standard sword swipes, and must be defeated using bombs or another item. Interestingly, in the original Japanese, these enemies are simply referred to as 'Kirby'.
In Kirby Star Allies, Hyness appears to implicate Kirby as a member of the ancient race responsible for the creation of many of the series' most powerful artifacts and who had also imprisoned Hyness on Jambandra ages ago. While this interpretation requires some speculation, it could imply that the ancients were similar to Kirby in appearance.
- There is some confusion as to whether the proper pluralization for Kirby is 'Kirbys' or 'Kirbies'. While 'Kirbys' is more common, both are used at some point in the series, so technically both are correct.