Undiscovered

Baby Pokémon such as Pichu, Togepi and Happiny are here, yet they still hatch from eggs: their evolved forms lay them. So are Nidorina and Nidoqueen, even though Nidoran♀ can breed, and every Ultra Beast and Paradox Pokémon.

The 151 species in the Undiscovered group, out of 1025 in the Pokédex, cannot breed with anything, not even Ditto, and none of them belongs to another group. Of these, 115 are genderless and the other 36 do have a gender, though they cannot lay eggs either. Among the 151, 92 are legendary or mythical.