I am sure I should categorize these, but for me I just enjoy listening to them all and the "hard" category that they would be put into do not really match the enjoyment or value I get from listening to these podcasts. For iOS podcast apps I recommend Overcast or Downcast.
My top picks:
These are the podcasts that I listen to as soon as possible.
Do By Friday (Friends challenge each other to do things each week)
ATP (Apple and tech news)
Back to Work (Life, productivity, comics, etc)
Judge John Hodgman (The internet meets "Judge Judy," with John Hodgman as judge)
Other great shows:
These are excellent shows that I listen to often but I might skip for a week or so then catch up.