To be completely honest, I don't see any passive income that isn't a scam. HYIP sites are "passive" income because you just send you money and then the website will make money for you. That's what HYIP sites say, that's what they promise. But, they are all just a scam. It's too good to be true, I won't even go near somewhere HYIP sites.
I think the only way that you'll earn some passive income is when you have your own company. It would take a lot of hard work, and you would have to hire a lot of people. A lot of money will be involved. When the company goes booming, you'll earn money as if it's a passive income because you don't have to work at all anymore. The people that you hired will be the ones doing the hard work and you're just there resting, watching your bank account's balance go up.
HYIPs and other scammy [so called] investments are not the only ways of reaching a passive income.
there are so many other methods in the world that you can use like what my top comment suggested - banks.
but also there is always investing in a business or buying something cheap and selling it high, it can be bitcoin, altcoin, gold, or real estate.
and so many different things that depending on where you live and how much money you have can be different.
Yeah and I think if you have good capital then you can invest that money in Government bonds where you can expect good passive income annually and its an safest investment to make.