I had to include this one! Blogging takes a lot of work and a lot of time, but is very flexible. You can write a post during a kid's nap and schedule social media posts during quiet times.
Small business owners, bloggers, and entrepreneurs all need help running their businesses, and you can help them! If you are good at office type work and organized, you can help with the tasks they need to run their business properly.
Paid online surveys are an easy way to start making good money. It takes a lot of time as each survey pays fairly little, but you can do them while your kids play in the park.
If you are good at writing, then you can market your skills as a freelance writer. Establishing yourself as a full-time freelance writer may take some time, but you can slowly build to the equivalent of a full-time job.