If you're a really good engineer (like I strongly believed I was) and don't have the network to find gigs (I live in Pakistan) freelance market places are great ideas on paper but never work out... Until I joined Toptal. They screened me to ensure I was a good developer (high quality supply of developers) and then worked with me to find a client that would be a good fit.
Since not everyone can get into the marketplace, it isn't a race to the lowest rate and they have the best clients I've ever worked with. At one point an old client emailed asking me to temporarily move to Australia for a project (although I declined)
You can work full-time, part-time, or even hourly. It's exactly what you're looking for!
Full disclosure: I later joined Toptal as an editor for their engineering publication [2] so I technically work there but this was all based on my experience as a freelancer there
[1]: referral link - topt.al/cppg [2]: https://www.toptal.com/developers/blog#contract-just-respect...