One of my most popular videos recently.
https://youtu.be/2rE5hB-EkGo The Saddle Rack
An evenly time, 4 beat gait that has no head nod (if you see a head not, the horse is leaning towards the foxtrot). I believe the saddle rack is the smoothest gait out there. It can be anywhere from 3 MPH up to 12-14 MPH. Trained with a low or level head, this gait can be sustained for long periods of time and isn't harmful to the horse (if the horse is conditioned).
Let me know if you have any questions.
Ivy Schexnayder
www.IvysHorses.com