​I’ve been into home décor lately and I had to turn to Etsy to find exactly what I wanted. I ended up purchasing digital files of the artwork I wanted printed out! The seller had made a bunch of wall art, digitized, and listed it on Etsy for instant download. There are other popular digital files on Etsy as well such as monthly planners. If you’re into graphic design this could be an amazing passive income idea for you.
What I’m doing: My realistic goal is to have a blended annual return of 2x the risk free rate. With a current 5% hurdle, I am not paying down mortgages that cost less than 4%. Debt at 5% is a wash. My realistic blue sky scenario is a 3-4X rate of return over the risk free rate which can be achieved with property, stocks so far for the past five years, and certain private equity investments. Where I am dragging is my blended average CD interest rate of roughly 3% from an old CD coming due. I’ve rolled some money into a 12-month CD with CIT Bank at 2.5%. It’s the best rate I can find. 
Rates / Annual Percentage Yield terms above are current as of the date indicated. These quotes are from banks, credit unions and thrifts, some of which have paid for a link to their website. Bank, thrift and credit unions are member FDIC or NCUA. Contact the bank for the terms and conditions that may apply to you. Rates are subject to change without notice and may not be the same at all branches.

Dividend investing is right up there for sure. You don’t have to charge $48. You can charge <$10 to boost sales. The internet has enabled so many creatives to publish their works at a low cost. People will surprise themselves if they try to create like when they were in school. The other reason why I have Creating Products edging out dividends is because of the much higher POTENTIAL to make a lot more money. For example, $20,000 a year in book sales requires $570,000 in dividend investments to replicate the same amount. Plus, there is capital risk. With book sales, there is a correlation with EFFORT, and you are not beholden to the whims of the markets.
They also launched an incredible Retirement Planning Calculator that pulls in real data from your linked accounts to run a Monte Carlo simulation model to output the most likely results of your financial future. I strongly suggest you run your own numbers, play around with the income and expense variables, and see how you stack up. It’s all free and easy to use.

One aspect you might want to add to your scoring is “inflation protection”. At one end, bonds and CDs generally pay a fixed nominal coupon that doesn’t rise with inflation. Stock dividends and Real estate rents (and underlying property value) tend to. Not reallly sure how P2P lending ranks- though I suppose the timeframes are fairly short (1 year or less?) and therefore the interest you receive takes into account the current risk free rate + a premium for your risk. Now that I think about it, P2P lending probably deserves a lower score in the activity column than bonds too (since you probably need to make new loans more often).
Thanks for asking. https://passiveincomemd.com/what-is-passive-income/ gives a good summary of the definition I use. But in brief, it’s income that isn’t proportional to the time you physically put into acquiring it. It doesn’t mean it’s not without work or effort. It’s just that most of the work is done up front and it continues to pay off long after that initial effort. Real estate fits into that box. There’s definitely a spectrum but compared to what we do as doctors, where our compensation is directly linked to our time, most of these things are quite passive.
Real estate is the obvious choice if you are going to make money on your money. I personally am not at the point where I can do any of this in a meaningful way BUT my parents are and they now own a couple homes outright and are collecting income from them to power their retirement income. It makes a lot more sense for anyone that has a chunk of cash sitting in the bank and are planning on slowly drawing from it because you technically still have all that money in a property (or multiple properties) and can sell them if you really need the lump sum of cash but you’ll earn great interest payments until you do that.