Like writing (above) transcription is another type of work that often equals a full-time income. However, there are lots of sites that accept beginners that don't pay very much for the audio transcribed. While a professional transcriber may not bother with the sites below, someone without the skill to be a professional could use them here and there for some quick extra cash:
The two popular ones are Poshmark and TheRealReal. Both make it dead simple to sell (and buy!) luxury items. The RealReal will pay you 60% of the sale price (more if you sell a lot) and Poshmark has a tiered commission structure. Sale prices under $15 pay a $2.95 flat fee and everything else is just 20%. Tradesy is another company and they take just 9%.
Webinars are quite possibly one of the most potent ways you can make an exorbitant amount of money online. Russell Brunson often says that if you do a webinar every single week for a year, you'll be a millionaire at the end of it. You'll need an audience to train and you'll need to know what you're talking about. Of course, this usually requires having a website and some semblance of an online presence.
Society6: Selling on Society6 is as easy as uploading a high-res file, then setting your retail price and your profit for each art print type and size. The site will produce, package, and ship the product for you. You can also add a large variety of other products, including phone cases, clothing, home decor, and bed and bath products, which have pre-set royalty payouts.
One of the cool things about Google AdSense is that it's so easy to get set up. If you have a blog or website, you can sign up for a free Google AdSense Account. From there, Google will give you a unique code that you will paste onto your website. Google takes it from there, tracking your page views, traffic, and earnings on your behalf. There is no upkeep or maintenance to get this thing going, which makes it a no-brainer if you have a website already.