Is there anything else in the tanoby ruins besides unown?

You're likely thinking of the Tanoby Ruins from the Pokémon games, specifically Pokémon Ruby, Sapphire, and Emerald. You're right, the ruins are home to Unown, but they also feature something else quite interesting:

* Hidden Power - The Tanoby Ruins are the only place in the Hoenn region where you can find a Hidden Power tutor, which can teach your Pokémon the move Hidden Power, with varying types depending on the individual Pokémon.

So, while Unown are the most prominent feature of the Tanoby Ruins, the Hidden Power tutor is another noteworthy element found there.