Is it safe to assume from the three companies you've listed that your industry/functional specialism is technology?You could start with a list (Times, Fortune, BusinessWeek, FastCompany, etc.) of most admired, fastest growing, best employer, etc. (you decide what's important to you). Filter by industry categorisation to get to the tech companies, take out clients who are not decent according to your personal experience working with them, add in any clients who aren't on the list but who are "decent" in your experience, and take it from there.