All Beta Pokémon are born with the BETA title, which is visible within your Pokémon's inventory listing. (Ex. LVL5 PKMN [β-Honoguma | Default | BETA])
Non-beta Pokémon, such as Bulbasaur, can only get the BETA title through being born from another Pokémon with the BETA Title or added with the use of a special item (Not revealed yet).
Within ONLY the Beta-Pokédex pages, a [ β ] beside a name represents a non-beta Pokémon with the BETA Title.
For example:
"Ivysaur [ β ]" is the same thing as "[Ivysaur | Default | BETA]"
It is an Ivysaur with the BETA title.
The BETA title allows the Pokémon to access any Beta's within their lineage, such as
- Evolving into a Beta Pokémon
- Devolving into a Beta Pokémon
- Showing design elements of a Beta through the intermediate trait.
Examples:
[Pikachu | Intermediate | BETA] would be able to show Gorochu design elements with the intermediate trait.
[Ivysaur | Default | BETA] would be able to evolve into Beta Venusaur
[β-Nyōsuka | Default | BETA] would be able to devolve into [Poliwhirl | Default | BETA]
Additionally, All betas that never got finalized into an official Pokémon (Such as β-Kakoroach, β-Cervarro, etc) will have a "β-" next to their name to inform the user that they are a Beta Exclusive Pokémon. Any who got finalized into an official Pokémon, such as Beta Venusaur -> Venusaur, will NOT have this symbol.
To evolve a Beta, you must use a Prehistoric Fragment.
Sources: The Cutting Room Floor, pokemon.fandom.com, Bulbapedia
Flying Dragon
Evolves into: Noivern [ β ]
An early version of Noibat.
Early designs for Noibat, looking slightly different from the final. It had more direct relevance to fruit bats, as labeled, which would later be described in the Ultra Sun/Moon Pokédex; it therefore featured several different colors depending on habitat, or the real-world geography in a similar way to Vivillon in the final.
Normal
Does not evolve.
An early version of Furfrou.
A furless design for Furfrou that didn't appear in the game at all.
Steel Fairy
Does not evolve.
An early version of Klefki.
Klefki's face was pink with a key motif. Its smile was replaced with a keyhole shaped mouth, as its initial face design was very similar to the coat of arms of the Holy See.
Fighting Flying
Does not evolve.
An early version of Hawlucha.
Hawlucha's green feathers were light blue and its red feathers were a dark blue. Its face is an even lighter blue than its wing feathers.
Rock Dragon
Evolves into: Tyrantrum [ β ]
An early version of Tyrunt.
Tyrunt was salmon colored, and had a different eye design.
Fire Water
Does not evolve.
An early version of Volcanion.
Volcanion was initially brown, before being made red later in development.
Fairy
Evolves into: Beta Floette or Floette [ β ]
An early version of Flabébé.
A completely different design that lacks a flower.
Fairy
Evolves from: Beta Flabébé or Flabébé [ β ]
Evolves into: Beta Florges or Florges [ β ]
An early version of Floette.
Again with a completely different design that lacks a flower.
Alt Design
Fairy
Evolves from: Beta Floette or Floette [ β ]
An early version of Florges.
An early version of Florges, with a design that somewhat resembles the final, but completely lacks the flower motif.
Alt Design
Flying Fairy
Does not evolve.
A scrapped flamingo Pokémon. The main image file contains two hidden alternate drawings that include an alternate pose and a slight design revision where the tuft on the back of its head is smaller.
Name by DeltaZero
(Flamingo+Flamenco)
Alt Design
Normal Poison
Evolves into: β-Hypnoxic
A scrapped two-stage set of chameleon Pokémon. May have been shelved due to an overlap with Kecleon. Three different designs are present for them, with slight differences between them. The final two revisions were found hidden in the file that has both of them together in the same image.
Name by DeltaZero
(Toxic+Chameleon)
Psychic Poison
Evolves from: β-Toxeleon
Same notes as previous.
Name by DeltaZero
(Hypnotize+Toxic)
Bug Water
Evolves into: β-Torreetle
A scrapped two-stage set of diving beetle Pokémon, as the text refers to them as.
Name by DeltaZero
(Dive+Beetle)
Bug Water
Evolves from: β-Deetle
Same notes as previous.
Name by DeltaZero
(Torrent+Beetle)
Rock Flying
Evolves into: β-Cassodaver
A scrapped two-stage set of cassowary Pokémon. May have intended to be a fossil Pokémon.
Name by DeltaZero
(Cassowary+Skull)
Rock Flying
Evolves from: β-Cassokull
Same notes as previous.
Name by DeltaZero
(Cassowary+Cadaver)
Grass
Evolves into: β-Pindaragon
A scrapped two-stage set of peanut-themed Pokémon. The initial listing for Pokémon in X & Y listed a two stage Nut and Nut Dragon Pokémon.
Name by DeltaZero
(Sprout+Peanut)
Grass Dragon
Evolves from: β-Sproutpea
Same notes as previous.
Name by ShadowChromia
(Pindar+Dragon)
Water
Does not evolve.
A scrapped small fish-like Pokémon was found with no additional information about it. Bears a resemblance to a boat's rudder.
Name by ShadowChromia
(Remora+Rudder)
Poison Dragon
Does not evolve.
Early version of Eternatus
A very humorous-looking placeholder model for Eternatus, which has more of a fish-like design