One of my favorites was where they reviewed an article about 22 dead bodies being the reasons behind the Flint river contamination. The original article stated that police discovered 22 corpses within the river and are claiming it is the reason behind the contamination. Snopes looked into the story and found it to be falsified, and released information about the actual issue taking place in Flint River.
I do not see evidence of bias in the few debunked stories I read, but that doesn't always mean there is none.
I look forward to using Snopes.com in the future so I can look into the truth behind some of the stories I see on social media.