I found this website (https://web.ground.news) that tracks how different news sources are reporting news stories. In many cases the differences amount to ignoring stories based on the political viewpoint of the outlet. The result is to create a blindspot for people who rely on news from a few source with similar politics.
Here is an example of a blindspot for the left:
Here is a recent example for blindspot for the right:
They also track words used to describe the same event that show how politics affects reporting, and provide weekly blindspot reports.
My observation is virtually everyone is subjected to news from the left. For example if I click on the Apple news app on my phone, it is heavily biased to stories from the left and many sources from the right never appear. I have to seek out sites from the right, but people who never get beyond the Apple news feed will miss a lot of stories.
I think the website is a good starting point for understanding which news stories become news and who they are reported.
Do see these reports as a useful service?
Do you see news blindspots as a real problem?