Here are some list of possible ways to earn money online,
1, Ad network or pay per click.
2, Build or buy website for flipping.
3, Get paid in online games.
4, Peer to peer lending.
5, Pay per download network.
6, Get paid to complete offers, surveys e.t.c.
7, Cpa net works.
8, Get involve in cryptocurrency.
9, Affiliate networks.
10, Pay per blog, review product on your blog.
There are many ways to earn online but this is just a summary, you will get more when you do your further research.
Getting Paid for Performing Simple Tasks
Getting Paid for Performing Simple Tasks