Through my personal travels I have found numerous different agents and agencies representing homes within my logic study area. However only one seems to have the competitive edge as far as listing volume.
Coldwell Banker Previews was the sign posted in front of most of the listed homes in the area. They specialize in luxury custom homes, and have an international clientele.
Coldwell Banker also had a few listings in the area, but significantly less than their sister company.
REMAX only had a handful of listings in the area.
Also, while I'm sure other Realtors have a small grip on the area, a name I recognized multiple times throughout my travels was Patricia Seide - Which may have something to do with Coldwell Banker taking most of the listings.