Hmm, only 5?
Healthcare Triage - Two segment show. One day is more news based and the other day is more in-depth. Goes into the science and what research actually shows. Has a great series of videos talking about the different kind of studies, how to put results into context (e.g. absolute vs relative risk), etc.
CrashCourse - Educational lessons on various subjects. I don't watch them all as some aren't that interesting to me or have a host I can't stand.
CGP Grey - Great videos explaining various subjects. Only does about 1 video a month.
PBS Space Time - Really well done videos explaining physics stuff. They did an entire series of videos talking about spacetime that built up along the way starting from a flat space, to a curved space, to a flat spacetime, to a curved spacetime. Had a decent video on blackholes that after a few watchings made it easier to understand blackholes. That had another one talking about tides and the moon's interactions that did a really good job of explaining it.
SciShow and
SciShow Space - Lumping these together as they are essentially the same format with one more space centric. A combination of news and explantation videos on various science and space topics.
I have a bunch more that I subscribe to and if the video looks interesting I'll watch.