That is exactly why there are MBA rankings. They do an excellent job of spotlighting less well known universities with excellent business schools, like Dartmouth, Duke and Emory. http://rankings.ft.com/businessschoolrankings/global-mba-ranking-2019

It also depends on what your goals are, which you haven't given any information about, and what you mean by 'not so well known.'

Beyond the ranked schools that Duncan has mentioned, there are also large numbers of 'below the radar' schools that may have international accreditation but don't often show up in the rankings. These business schools are often hosted by public / state schools - Louisiana State University, CUNY (New York), University of Florida, etc.

Also, check out the US News ranking. I would say that anything ranked 50+ are 'lesser known.'

Mainly regionally focused schools to be sure, but in the 50s-60s there are schools like Rutgers, Northeastern, GWU... each with their own strengths. All solid schools and not typically thought of as 'highly ranked.'

Thanks for all the help! I was aware of some of these business schools but not all. I will research them and see what might work for me. Thanks again!