All of these are on my phone podcast app...I use overcast by the way...much prefer it to the stock iPhone app. I have about 20 channels loaded. These are the top few where I always find value.
The Tim Ferriss Show -The best podcast out there for optimizing human performance!
Krista Tippett's On Being is stellar
Freakonomics Radio - Don't let the title scare you. These are the guys that wrote the book by that name but the broadly interview and you will be smart for it.
Dave Asprey's BulletProof Radio
While not a podcast - Google Talks are free online and provide a deep dive on all sorts of important topics. You can't help but get smarter, hear fresh ideas and end up stimulated!