I subscribed to Harness Breeders last year and this week I received their 2019-2020 Stallion Guide
First of all I should say it is an attractive production and a valuable resource

But I was somewhat surprised that it was not more comprehensive than it is.
I know it is paid advertising and it comes down to which and what studs will pay for its production
But not only are many small studs not represented but also some major ones especially for the trotting gait. Even some of the featured studs do not include all the stallions they stand

So don't forget the HRA link for a fuller picture