Question: can kadabra evolve without trading?
Answer: You don't. There is no way to evolve a Kadabra, Haunter, Onix, etc. in any of the core Pokémon games without involving some kind of trade, and it's one of the things that Pokémon desperately needs to fix. ... There is no way to evolve a Kadabra, Haunter, Onix, etc.