There's also:
- PeoplePerHour.co.uk (UK based, not sure of international presence)
- Freelancer.com
- Toptal (but I think they have some sort of approval process that may be a bit arduous)
- Guru.com
- Codeable.io
- Outsourcely.com
- Truelancer.com
- Konker
- Servicescape
- Solidgig (but stronger for design and marketing/SEO roles, I think - considered dropping into the category below)
- Hubstaff Talent
- FlexJobs (but more oriented toward IT and accounting than software development; again, considered dropping into the more specalised category below)
Additional specialist companies I'm aware of that target roles other than developers:
- 99Designs (for, you guessed it, designers and UX) - https://99designs.co.uk/
- Savio (market researchers) - https://savio.pro/
- F-LEX (legal) - https://flex.legal/
Hope you manage to pick up more work soon, but also that you manage to get yours and your clients money back from Upwork.