I have had interviews with several of the companies on this list and I am currently working for one of them. They mostly teach business English, but most of them offer test preparation, group and individual classes too.
According to their application they want teachers who are able to work in the USA legally. Click here for the Open English reviews and comments page.
They have their own platform and they are looking to hire business English teachers.
Click here for the comments and the Redwood Language review page.
They are looking for university graduates and students, who can also help to improve their curriculum and their IT. Click here for the comments and the Way Up review page. Language Center (link removed as they no longer need teachers) is in Virginia and they teach more languages than just English. English Key is based in New Hampshire and is looking to hire native speakers.
They want someone who can work at least 10 hours a week in the afternoons and evenings (Eastern Standard Time).