Priceless one
Tonio is a short form of Antonio, the Spanish and Italian derivative of the Roman family name Antonius. While its exact etymology is debated, it is most commonly associated with the meaning 'priceless' or 'inestimable.' It carries a spirited, European flair while remaining approachable.
Less common today
Tonio isn't in the latest US Top 1000. It last peaked at #2,594 in 1990.
Protagonist of the eponymous novella by Thomas Mann · Tonio Kröger
A character in the opera Pagliacci · Pagliacci
A chef and Stand user in the anime series · JoJo's Bizarre Adventure
US births per 5-year period, 1990–present (SSA data).