Media Bias Fact Check itself it’s a good start, but it can also be a bit biased when judging whether a source is left or right leaning.
Yes, it is very difficult that there is no bias. In any case, that classification between left and right was not what I was interested in showing or highlighting on that site.
Anyways, when it comes to credibility, it can be accurate.
Ground News may show the left/right bias. But I personally don’t see the point. Both news sources can be right. The physical world is not left or right. But it can be helpful to know if a news source has a bias. But then I personally would not check that source. Journalism should be about impartial reporting of events.
MBFC is a useful tool.
For example, when making an argument, linking the sources you are using with fact checks is a way of being less likely to be denied by a skeptic. It does not prevent denialists from denying your argument altogether, but it makes it more trustworthy.