Suggest to me some Roku channels

I am just starting to use the Roku for more than a netflix box. Amazon, Netflix, YouTube and Night Flight were no brainers. Just found the PBS channel so my woodwrights shop fix is taken care of

Now I understand there is a lot of pretty much hidden content. I have found a few lists with a ton of out of date info.

Suggestions?

In reply to Jumper K. Balls:

Lucas oil has good content but its a paid channel like netflix is. I'm amazed the RedBull channel is free, it has some moto gp content, uci mountain bike races, world rally, and alot of good music and documentaries.

Kindle(?) was a little heavy on advertisement, but had great music biographies and such if I remember correctly.