I'm assuming you're talking about passive income other than from investments.
Blogs take a lot of consistent, high quality work to be successful. I wouldn't consider them passive or even semi-passive.
Informative Youtube videos might work if you can think of things that people are searching for, and then post "how to" videos or something similar. Same thing with self-publishing an e-book on Amazon. I believe MMM mentioned in his article on how to build a shower that he considered making an instructional e-book on how to remodel a shower that would sell for a few dollars. This would take a fair amount of upfront work, but then you could sit back and wait for it to work.
There are lots of other ideas to generate non-investment passive income. For example, depending on where you live, you might be able to rent ad space in your lawn or on your car for a small sum per month. There are programs where you can donate your computer's processing power while you sleep at night, so you might be able to find a place that would rent this processing power for a small rate. You can "mine" for Bitcoins (although I've heard this can cost more in electricity than most people can make). There's a lot out there, the key is just to be creative.
