Only 24 pets in the dataset answer to Onix, putting it at rank 3,424 — but among the generation that grew up trading holographic cards and grinding Pokémon Red on a Game Boy, this name is an instant recognition signal.
Pokémon No. 95
Onix is the Rock/Ground-type Pokémon introduced in Generation I, a massive serpent of boulders that served as Brock's signature partner in the original anime. The name itself is a respelling of "onyx," the banded silicate gemstone — fitting for a creature whose body is literally made of stone. I have a soft spot for this one: Onix was the first gym badge obstacle many of us faced, and getting past Brock with a starter Pokémon felt genuinely earned. Great Danes and Rottweilers pull off the name's monumental energy well.
The Gemstone Connection
Strip away the Pokémon reference and you still have a strong pet name. Onyx the stone has been prized since antiquity — ancient Greeks used it for carved cameos, and it carries associations with strength, protection, and mystery. A black cat or a dark-coated dog named Onix wears both meanings at once: the gemstone's gravity and the Pokémon's retro gaming credibility. That dual resonance is exactly why the name works for owners who want something distinctive without explaining it every time.
Who Chooses Onix
Onix owners are almost certainly millennials or older Gen Z — the Pokémon generation. It skews toward male pets and tends to land on animals with either an imposing build or an unexpectedly dark coat. If you like Blastoise but want something shorter, or if you love gemstone names like Onyx but prefer the gaming spelling, Onix hits that crossroads perfectly.