Some good videos

Pull Less Bend More: 2017 World Champion Manoj Vasudevan

Speech that made Obama the President

2013 World Champion

Power of Words: 2015 World Champion 

"I have a dream": by Martin Luther King Jr.

Lance Miller:2005 World Champion

I See Something: 2014 World Champion

5 Public Speaking Tips

Patricia Fripp: Tips for a good speech