You could also opt to use existing websites for making money. These include both active income and passive income methods. For example, you could sell some used items or invest in creating some digital designs that then can be sold on merchandise. Again, devote a sizable portion of your time to passive income so that you can slowly build up earnings that will arrive on autopilot without any extra added effort. 
Build up a following on your Instagram account and you could quickly be making extra money online. Major brands, gear companies, and even startups are willing to shell out $500-$5,000+ per post to get in front of your audience. While it’s getting harder and harder to build a massive Instagram audience, if you already have a solid niche and are posting quality content regularly with a great camera for taking Instagram photos, with a few small tweaks you can make yourself an influencer. Check out this awesome article from Shopify on how to build and grow your Instagram following to get started.
Hi, Jamie! Very good list. I needed something like this for 2018 so that I know what to target in the future blogs I create. As for now, I’m comfortable using SiteGround affiliate network and it’s pretty good actually. Their hosting service is pretty much the best considered its price. I’ve tried others but SiteGround stands out. I’ll also try new affiliate networks, something from the list you have just provided. I think Amazon is too saturated at the moment, and I need a better network. 2018 will be interesting indeed.

Affiliate marketing has grown quickly since its inception. The e-commerce website, viewed as a marketing toy in the early days of the Internet, became an integrated part of the overall business plan and in some cases grew to a bigger business than the existing offline business. According to one report, the total sales amount generated through affiliate networks in 2006 was £2.16 billion in the United Kingdom alone. The estimates were £1.35 billion in sales in 2005.[19] MarketingSherpa's research team estimated that, in 2006, affiliates worldwide earned US$6.5 billion in bounty and commissions from a variety of sources in retail, personal finance, gaming and gambling, travel, telecom, education, publishing, and forms of lead generation other than contextual advertising programs.[20]
Etsy: While Etsy's popularity has declined recently, it's still a great resource for selling handmade items online. No need for complex ecommerce sites or merchant accounts or any sort of automation. The company takes a commission of every sale and charges a small listing fee per item. But many still use Etsy as their primary source of income. The best part is that you can also sell digital products on here such as poster designs. 
The organizing principle behind this grouping, appropriate economic units, is relatively simple: if the activities are located in the same geographic area; if the activities have similarities in the types of business; or if the activities are somehow interdependent, for instance, if they have the same customers, employees or use a single set of books for accounting.
The U.S. Internal Revenue Service categorizes income into three broad types, active income, passive income, and portfolio income.[1] It defines passive income as only coming from two sources: rental activity or "trade or business activities in which you do not materially participate."[2][3] Other financial and government institutions also recognize it as an income obtained as a result of capital growth or in relation to negative gearing. Passive income is usually taxable.
If you know anything well, a place, how to fix something, how to make something, how to do something, you can write a guide for it. You can sell your guide as an e-book, offer it as a download for a fee on your site or reach out to bloggers with similar content and ask if they will offer it as a paid download on their website (for a price of course).

This isn’t to scare you off. I simply want you to know that this guide is going to focus solely on ways to make real, sustainable extra income online. Not just a few bucks. I want to share all the mistakes I've made that got me to where I am now so that you don’t have to go through them, and can build a successful online source of income for yourself.
Often, what happens is that we run into unscrupulous Internet Marketers (IMs) who have less-than altruistic intentions of extracting money from you rather than helping you to make it. However, this isn't something new. People have been falling for networking marketing, pyramid schemes, and affiliate marketing scams since before the start of the net.