Here is a list of all the microstock sites where i sell my pictures. The ranking is based on my own experiences with amount of sales, upload procedures and payout. I also added a link to my own portfolios and a link to sign up as a contributor.
Most of the sites only accept high resolution images above 3000px on the long side. You can also submit vector illustrations and footage on some of the sites.
Do you have knowledge of any other microstock sites i missed on my list? Please use my contact form and let me know, and i will add it as soon as possible.