Thank for this extensive work. When you make extra money you need to think simple. First thing you should consider is whatever you do must be safe enough that you don’t lose your initial investment as well. Also, look at the ways you can reduce your costs. This could be car insurance savings or paying back expensive loans or card balances. Saving is making money as well.

Truebill is an app that helps you save money by identifying recurring subscriptions and other bills and helping you cut costs by negotiating better rates and fees. One of their partnerships is with Acradia Power, which has the potential to save you up to 30% on your electric bill. It searches for better power rates in areas where competition is allowed, and it locks in the better prices for you.
Ebooks are one of my favorite sources of passive income. Now, you can do this the simple way and just publish it on Amazon's KDP. Or, you can go all out and build yourself a book funnel. Book funnels are powerful, but they won't be fully passive. For example, if you do a free-plus-shipping offer for your ebook (converting it into a physical book), you'll need to create some one-time offers (i.e. extra training) and up-sells (i.e. an audiobook). But, a book funnel can be very powerful.
If you’ve ever thought to yourself, “I wish there was a product that did this,” then invent it! Create a product, medical or otherwise, and sell it as a company or get royalties for it. It’s not impossible to figure out, I have many friends who have taken a concept to market. Don’t overlook an invention as a fantastic means of attaining passive income.
Sell an eBook Online – Self Publishing is mainstream today. When you purchase an eBook off of Amazon there’s a pretty good chance you’re buying a self-published book. Self-publishing is also ridiculously easy. I tried this a few years ago and couldn’t believe how simple the process was. To self-publish a book you’ll first need to write and edit it, create a cover, and then upload to a program such as Amazon’s Kindle Direct Publishing. Don’t expect instant success though. There will need to be a lot of upfront marketing before you can turn this into a passive income stream.