How do you find good voice/dialogue samples for mixes?

Hey all!
I've been DJing since April, starting to get more serious about it now and looking at ways to step up my game. One thing that lots of DJs I admire do is weave clips from performers during live shows, movies, interviews, etc into their mixes. Often these are faded in or dropped during a transition.
So, right now I'm practicing a funk/soul mix for a theme party at the end of the month, and trying to find some good clips to use during the set. I've been searching YouTube for various performers (Aretha Franklin, Diana Ross, Sam Cooke, Wilson Pickett, etc) and looking for their interviews... not having much luck with that so far.
Do any of you have tips on how you've gathered non-musical samples for use in your sets? I've started jotting down when I hear something that sounds promising, but I'd like to actively search more material out.
Thanks! :)