They predicted Trump's win in 2016 when other polls showed Clinton up, but the 2016 polls were showing a tighter match up than 2020 is today. However, Trafalgar's spread from other existing polls today is much wider. Their polls in the swing states are generally in line with the actual 2016 results. Apparently they ask respondents who they think their neighbors are voting for and factor that into their analysis. I think this could be biased and over count the Trump vote since people don't want to "get fooled again". Trump voters are obviously way more enthusiastic than Biden voters. Biden excites almost nobody, but there's obviously a huge enthusiastic "anybody but Trump" vote.
Here are some of their polls:
https://www.thetrafalgargroup.org/
Here are some of their polls:
https://www.thetrafalgargroup.org/