Ebooks selling is also one passive income and there plenty of places to sell them like Amazon.

Few ways I have done it which is really passive (means not even managing anything)
- Hard Money Loans and Equity deals of Real Estate
- Other kind if diverse loan types again where someone else is managing the serving collection and legal work
- Getting land (since it doesn't require much management) and selling for profit or renting for agriculture
- Of course Investing in dividend stocks is the most common and most preferred day
- Investing in stocks along with conservative option writing strategies.
- CDs and bank interest - but currently its very low but just few years ago you could get 3% for 5 years
- investing in precious metals - it doesn't generate any income but can be sold for capital gains - look at a gold chart of 20 years!

Of course I might be missing multiple other ways that are possible.

Assuming that the risk is managed and your own involvement is limited to only the spare time you can't productively employ otherwise, there are a lot of passive income avenues. But don't forget, to earn passive income, you'll have to invest either time/effort or money in consideration. Or else, they have unavoidable downsides. Here are a few examples.

1-Property Rental (Financial investment needed)
2-Youtube channel monetization (Deep expertise and fanbase needed)
3- Vacation getaway management(Financial investment and self involvement required). It's a full time job but doesn't feel that way.
4- Royalty (Write a book or sell a self developed mobile application)
5- Share dividends (this is as close to a 100% passive income as it gets. RISKY)
6- Bank deposit interest (NOT lucrative)

Some of the best truly passive income ideas that I have personally experimented with, include: Stock Photography, Self-Publishing with Amazon KDP, Selling a Digital Product on Gumroad or Etsy, or incorporating Affiliate Links into blog posts.

I've written a more detailed post, here:
https://medium.com/escaping-the-9-to-5/passive-income-ideas-for-2020-7a76c9d6218

Think of returns are being inversely propositional to effort. No effort is very passive, but the returns are not awesome. Great returns are available, but in my experience, they are not passive. There's due diligence on the front, or management on the backend, to make a great return happen.

CD's / Money market accounts yield small returns, and are very passive.
Less passive are annuity products. You have to do your homework on the front end, but it can yield well.

Hard money lending is great. It will be work if there is a default, but the returns are very good, and it's collateralized debt, meaning you gain an asset if you're the first on the loan and there is a default. The way it becomes non-passive is if you collect.

If you start talking about business, then passive probably isn't going to happen (at least not long term). It's going to need active management. The returns are generally much better, but it's not passive.

I hope that helps!

Passive income has long been the holy grail for entrepreneurs looking to free up their time, untethering the cord of daily duties and responsibilities from the potential to generate healthy monthly revenues. While the importance of passive income is not often doubted, the monumental hurdle often required to achieve a respectable amount of cash flow from automatically recurring revenue streams is often too great for most to bear. Clearly, it is hard to generate passive income. It requires the upfront investment of a significant amount of our time, usually with little to no returns for extended periods. We can go months and even years without a single dollar produced from passive income activities, making even the most astute entrepreneur shake their head in sheer and utter frustration. Here are few ways of earning passive income:
1. Start a blog: The most important method for generating passive income is to start a blog. Blogs can generate a tremendous amount of income, but not quickly. If you plan to start a blog, understand that it is going to take a vast amount of work and time to succeed. Regardless of your niche, if you have a clear understanding of things like searching engine optimization, social media marketing and the ability to write high-value content, then you will succeed with a blog. Once your blog becomes popular, it provides you with the platform and audience to generate multiple streams of revenue by marketing relevant products and services to your visitors.
2. Write and publish an eBook: Another great method for generating a respectable amount of passive income is to write and publish an eBook. Non-fiction eBooks that help to educate your audience on topics such as online marketing, business, or other self-development areas, are going to sell far better than fiction books at the outset. Clearly, fiction can make tremendous amounts of money, but it is also highly competitive if you are not an already-established writer with an existing following. Utilize the Amazon Kindle Direct Publishing platform and publish eBooks that will fill an existing need in popular niches where you have some level of expertise.
3. Create an online course: Have a technical skill? Want to convey that skill to others out there while generating a healthy passive income stream? Creating an online course on Udemy is a great way to automate some of your cash flow. However, like any other income stream that is passive, it takes a significant amount of effort on the front end. There are so many things that can be taught through an online course.
4. Produce an audiobook: Leverage Audible's ACX platform to push out your audiobooks to the world's most robust platforms such as Audible and iTunes. If you have specialized knowledge or advanced skill sets in some area, you could opt to teach them through audiobooks. However, you must focus on delivering an enormous amount of value and ensure that you have a high-quality production. Do not try to slap things together and expect to earn any money online.
5. Become an affiliate marketer: Affiliate marketing is likely one of the most powerful ways that you can produce multiple passive income streams. However, this is not easy by any measure. To succeed at affiliate marketing, you need a large following of users. In other words, you need a big platform and audience. When you do not have a platform or audience, you need to run ads, which can get costly. If you know what you are doing and you are a seasoned internet marketer (IM), you will succeed. But it takes time to learn the ropes. Still, this is a great way to sell products and services that you do not own, effectively becoming like a broker while earning a healthy passive income stream.
6. Build a sales funnel: Anyone in the marketing business understands the concept of sales funnels. Sales funnels conceptualize the process of taking prospective customers from browsers to buyers. However, building the proper sales funnel is no easy task. It requires a serious amount of upfront investment of your time, and it also requires lots of browsers to drop into the top of the funnel. To build your sales funnel, you need to offer something in exchange for an email address, effectively creating a free offer. Sign up to a system like Aweber or Mail Chimp and work on building out your sales funnel. Create a free offer and build an automated email series that will move your leads up the value ladder of products that you are selling.
7. Develop a smartphone app: I know it is not easy to develop a smartphone app. You either need a lot of skill or a bit of money to get someone to make your vision into a reality, but it is still possible. While the overnight gold rush to app riches might be over, you can still earn a respectable income if you develop the right app. If you can create the next Uber, then great. If not, you can opt for some niche app that will help to solve a problem or fill a need that might not have yet been properly covered. Think you can do something better? Why not give it a shot? If you are at all technical and understand the dynamics of business and smartphone applications, this is worth your while.
8. Earn real estate rental income: Real estate has long been the source of passive income for ages. Investors and owners have opted to rent out homes, apartments, condos, and office space to generate a healthy monthly revenue. Clearly, real estate is a great source for generating some automatic income, but it also requires a sizable upfront investment. If you have extra cash lying around, you can certainly opt to invest in some real estate. You can purchase real estate to rent out to long-term tenants or you can try your hand at vacation rentals through sites like Airbnb or VRBO. Either way you look at it, this is a great passive income idea if you have the cash lying around.
9. Sell digital products on Etsy: Etsy is a massive resource for people wanting to sell all types of handcrafted goods. But did you also know that you can sell digital products on Etsy? These digital products require little to no maintenance once they are up and running. All you need to do is put the time into creating the digital products and setup quality listings Clearly, this will require some maintenance on your part and ensuring that the right traffic hits your listings. However, digital products require virtually no overhead and will sell automatically if they are high in quality and are appealing to the relevant audience that you are targeting.
10. Generate royalties from jingles or audio tracks: If you're musically inclined, one idea for generating some passive income could be to create jingles or audio tracks that you can then license out through popular websites such as Audio Socket, Sound Cloud or Song Freedom, just to name a few. Clearly, this is not easy. But it is well worth your time if you can come up with something great. Do your research and due diligence to create audio tracks that are appealing to a large audience. Search for other popular tracks that are being heavily licensed and see what they are doing that you could try to replicate in some format, while not outright duplicating.
11. Make YouTube video tutorials: YouTube is a great resource for earning a large stream of passive income. While it is not easy, and it will effectively take millions upon millions of views to earn some semblance of a real income from this stream, YouTube does offer a very cost-effective avenue to market. Research what the most popular YouTubers are doing. For example, Blippi, which is a kid's series created by creative entrepreneur, Stevin John, helps to teach children about all types of subjects and has become one of the most popular YouTube series in its niche with over 500 million views in the past couple of years alone. Seek out successful people and try to replicate their formulas while being unique.
12. Sell professional photos online: Another avenue for passive income is to leverage photo-selling websites such as iStockPhoto and Shutter Stock to earn money while you sleep. Clearly, you need to understand photography and things like Photoshop if you are serious about succeeding in the photo-selling business. There is a lot of competition when engaged in this line of work. However, if you have a knack for photography, then selling your photos online should come almost naturally to you. Get good with photo-editing software and find your niche. Whether it is portraits, landscape photography, business photography, or something else, find it and stick to it.
13. Use cash back credit cards: Cash back credit cards offer a great resource for earning some passive income, especially if you are already going to be spending the money. While this revenue stream likely will not make you rich, it will help give you some kickbacks on money that you're already likely spending in your day-to-day life. Do a few searches online for the best cash back credit cards and sift through all the posts that detail what the right card would be to fit the bill. Be wary of linking through on some of the posts that might try to push you towards the card that will help them earn the greatest income by referring you to it.
14. Purchase dividend stocks: Dividend stocks are great resource for generating passive income. You also will not need to sell the stock to generate that income. However, you will need to buy a significant number of shares to see a healthy stream of revenue from whatever dividend stock you end up selecting. Do the proper research and due diligence on finding the right dividend stocks. You do not need to start out by knowing everything, but you do need a desire to learn and understand. Start small and build up from there while constantly keeping an eye out for high-income producing dividend stocks.
15. Invest through peer-to-peer lending platforms: Peer-to-peer lending platforms such as the Lending Club and the Funding Circle make it easy and straightforward to invest in people and businesses to generate a passive income stream from interest payments. Many of these sites have accurate algorithms that will predict risk, taking much of the guesswork out of the equation for you. Clearly, this will require some upfront investment. If you have some money stashed away, this might be a good avenue for investment without having to rely on low-interest-producing CDs at banks or high-risk stocks. Do the research and judge for yourself on whether this passive income idea works for you.
16. Become an ATM vendor: Depending on where you live, you could quite possibly make some great passive income by setting up ATMs in a variety of locations such as small corner stores or in malls and so on. Locate a good company that will allow you to place their ATMs at various businesses and earn a small percentage of the income that these generate. Outside ATM machines can charge upwards of $5 per transaction, and you could get a small piece of that. On volume, this can amount to a lot of money. Clearly there is some maintenance involved in this and it is not fully passive, but it is a great resource for earning a respectable amount of monthly cash flow depending on the volume of ATMs you're able to setup.
17. Build niche or "guide" websites for lead or referral income: If you have an understanding of SEO and online marketing, you might want to build niche or guide websites to help generate leads and referral income. Popular industries include insurance, credit cards, the make money niche, diets, and weight loss, amongst many others. Find something that you know and ensure that you source the right relationships with the right companies to sell your leads, or make sure that people are referred to the right products or services that will allow you to earn a commission with each subsequent sale.

Besides if you do have any questions give me a call: https://clarity.fm/joy-brotonath