Pokemon Platinum Part #11 - Right Angle

Onix Pokédex: stats, moves, evolution & locations

LIVE Shiny Onix in Pokemon Platinum via Random Encounters (phase 2)

Let's Play Pokemon: Platinum - Part 26 - Onix & Mt. Coronet

Who decided that Onix should have a ridicuously difficult catch rate?

Pokemon Platinum Waterlocke League Plan + Story by ZoraTheTwilightDrake on DeviantArt

Pokémon Adventures: Diamond and Pearl/Platinum, Vol. 9, Book by Hidenori Kusaka, Satoshi Yamamoto, Official Publisher Page

Does Onix evolve into Steelix? - Quora

Pokémon Adventures: Diamond and Pearl/Platinum, Vol. 8, Book by Hidenori Kusaka, Satoshi Yamamoto, Official Publisher Page

Following the Trend, here's every Pokemon you can get in Pokemon Platinum before the first gym. : r/pokemon

Alolan Onix by BigBadSkullBoss on DeviantArt