According to the textbook, Stand Up, Speak Out: The Practice and Ethics of Public Speaking, persuasive speeches seek to change the audience's "attitudes, values, [or] beliefs" or their "behavior" [chapter 17].
NON-PARTISAN: These sites endeavor to remain neutral. This is not an exhaustive list, but may give you a good start.
LEFT or RIGHT PERSPECTIVE: This is not an exhaustive list. Just a way to get started:
|News & Commentary with a Left-Leaning Perspective||News & Comomentary with a Right-Leaning Perspective|