Wow! What an awesome list! My favorite is the stock photography because I love photography. I have had some success there, particularly with one photo I make some decent income from. I think the key with stock photography is finding a shot that is high demand. Then, find a new unique way to frame that shot. This is the reason my St. Louis Arch photo is a top 10 on both ShutterStock and iStockPhoto. Thanks for the awesome ideas above!
5. Make sure you are properly diversified. Capital preservation is underrated. We saw a lost decade for tech stocks between 2000 and 2010 after the first dot-com bubble burst. It actually took 13 years for Nasdaq investors to get back to even. Investors in the Borsa Istanbul stock market index just gave up 10 years' worth of gains after they saw a plunge in their currency, partially due to increased tariffs by the US and a lack of confidence in the government. Your passive income needs to be properly diversified in order to take the hits.
A renowned lucrative asset class, real estate—both residential and commercial—has become one of the most popular ways to produce residual income. Traditionally, building a residual income stream through real estate investing has required a large upfront investment of both of time and money. But thanks to new investment vehicles, those interested in earning passive income through real estate investments have several options.

I have only dabbled in drop-shipping before when I had an eCommerce platform 6 years ago or so. I think it is something that you could do on the side, but you would want to do in depth research on the industry you want to get into before setting up shop. It may be a little less passive up front, but over time you could take your hands off the wheel.
Accretion/dilution analysis Adjusted present value Associate company Business valuation Conglomerate discount Cost of capital Weighted average Discounted cash flow Economic value added Enterprise value Fairness opinion Financial modeling Free cash flow Free cash flow to equity Market value added Minority interest Modigliani–Miller theorem Net present value Pure play Real options Residual income Stock valuation Sum-of-the-parts analysis Tax shield Terminal value Valuation using multiples

One of the most well known ways of generating residual income is through ownership of stock in a publicly-traded company. Residual income streams can also include things like royalties from the sale of a book or song. Today, there are also several online platforms like Lending Club or Prosper that allow you to invest in personal or small business loans.

Residual income is the best model for money generation. Once you master and build up one avenue, you can devote your time and money into another avenue. Eventually you start reaping the benefits of multiple residual income avenues. Enabling you to have complete financial and time freedom. I recommend to all people to build these types of asset models as they can greatly improve their life.