Amplitube 3 and Bias fx both have readily available torrents. I was happy enough with old versions of Amplitube that I purchased Amplitube 5 and have been really happy with it. They have plenty of metal rigs, but I haven’t personally used them as I mostly stick with the tweed and plexi stuff.
Neural DSP is another paid option but everything I’ve heard is that they’re the cream of the crop for metal tones. They also offer a 14 day trial.