All of them have bias. The Leftist ones are EXTREMELY partisan, 24/7. It's the main reason why I don't watch them, in addition to them spewing nothing but hatred towards ANYONE on the Right of them (even moderates). That includes all but Fox News and C-Span on this list.
Fox News doesn't get too partisan until Tucker Carlson, Sean Hannity, and Laura Ingraham. You'll see some elements of it at different times, but for the most part, based on what I heard others that use to work there have said, Fox News is far more moderate than what most people think. I've even noticed it, and, honestly, they moved a little more towards the Left over the past year or 2 (with the exception of the prime time hosts). Not much, but it's just enough to notice. It just has more conservatives come on than any other news organization. People tend to forget or simply not pay close enough attention that during the 2016 Election, Fox News (again, except for the prime time hosts) was in the tank for Jeb Bush, a moderate. They practically sang this guy's praises. Everyone else, except for the likes of John Kasich, at times Marco Rubio and Chris Christie, they threw under the bus (which included Trump). So to say that over half of Fox News is conservative is pretty deceiving.
C-Span, I don't even know if you can even consider them a news organization. They're more of a meeting channel, if that makes sense, where all they do is broadcast meetings, hearings, conferences, etc. Whenever some of their "anchors" speak their opinions, though, they're very much on the Left. I only watch them in case if a major gathering is getting ready to happen. That's it. Other than that, I don't tune in.
The bottom line is there is going to be bias, regardless, in form or another. It's just the extreme Left wing ones are nothing but partisan politics all day long.