It seems to me that the perfect cmbination of volatility and profitability is the classic of forex trading. I'm talking about currency pairs. They have moderate volatility and as it seems to me the most favorable trading connditions.

I think it will still be GBP currency pairs and gold. These are the most volatile assets among those presented here.

But if I were you I wouldn't chase the most volatile ones. Instead I would focus on the instruments that you analyze the best. Cuz volatile assets that you can't trade will bring you nothing but losses and despair. Volatility doesn't necessarily translate into profits directly. Be careful.